Could you run the IDE with -J-Dorg.netbeans.modules.masterfs.watcher.disable
=true for a few days and let me know if the problem persists? And could you attach an error stacktrace also from the failed revert action?

Created attachment 109261 [details]
stack trace from messages.log

Started NetBeans with args as suggested. Tried to commit file changes. Got message that nbproject directory is locked and asked to perform a cleanup. Executing cleanup resulted in:

org.tigris.subversion.javahl.ClientException: Cannot rename file '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/tmp/entries' to '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/entries'

Logging from the last attempt:


INFO [org.netbeans.modules.subversion]: org.tigris.subversion.javahl.ClientException: svn: Working copy '/Users/user1/Applications/tomcat/webapps/project1/nbproject' locked; try performing 'cleanup'
org.tmatesoft.svn.core.SVNException: svn: Working copy '/Users/user1/Applications/tomcat/webapps/project1/nbproject' locked; try performing 'cleanup'
	at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:64)
	at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:51)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea14.lock(SVNAdminArea14.java:1562)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNWCAccess.doOpen(SVNWCAccess.java:370)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNWCAccess.open(SVNWCAccess.java:274)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNWCAccess.open(SVNWCAccess.java:267)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNWCAccess.open(SVNWCAccess.java:263)
	at org.tmatesoft.svn.core.internal.wc.SVNCommitUtil.createCommitWCAccess(SVNCommitUtil.java:247)
	at org.tmatesoft.svn.core.wc.SVNCommitClient.doCollectCommitItems(SVNCommitClient.java:1191)
	at org.tmatesoft.svn.core.wc.SVNCommitClient.doCommit(SVNCommitClient.java:825)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.commit(SVNClientImpl.java:665)
Caused: org.tigris.subversion.javahl.ClientException: svn: Working copy '/Users/user1/Applications/tomcat/webapps/project1/nbproject' locked; try performing 'cleanup'
	at org.tigris.subversion.javahl.JavaHLObjectFactory.throwException(JavaHLObjectFactory.java:778)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.throwException(SVNClientImpl.java:1850)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.commit(SVNClientImpl.java:667)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.commit(SVNClientImpl.java:648)
	at org.tigris.subversion.svnclientadapter.javahl.AbstractJhlClientAdapter.commit(AbstractJhlClientAdapter.java:319)
Caused: org.tigris.subversion.svnclientadapter.SVNClientException
	at org.tigris.subversion.svnclientadapter.javahl.AbstractJhlClientAdapter.commit(AbstractJhlClientAdapter.java:325)
	at org.tigris.subversion.svnclientadapter.javahl.AbstractJhlClientAdapter.commit(AbstractJhlClientAdapter.java:292)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler.handle(SvnClientInvocationHandler.java:367)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler.invokeMethod(SvnClientInvocationHandler.java:331)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler$2.call(SvnClientInvocationHandler.java:179)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler.invoke(SvnClientInvocationHandler.java:185)
	at $Proxy19.commit(Unknown Source)
	at org.netbeans.modules.subversion.ui.commit.CommitAction$CommitCmd.commitFiles(CommitAction.java:748)
	at org.netbeans.modules.subversion.ui.commit.CommitAction$CommitCmd.access$600(CommitAction.java:732)
[catch] at org.netbeans.modules.subversion.ui.commit.CommitAction.performCommit(CommitAction.java:685)
	at org.netbeans.modules.subversion.ui.commit.CommitAction.performCommit(CommitAction.java:550)
	at org.netbeans.modules.subversion.ui.commit.CommitAction.access$100(CommitAction.java:106)
	at org.netbeans.modules.subversion.ui.commit.CommitAction$4.perform(CommitAction.java:372)
	at org.netbeans.modules.subversion.client.SvnProgressSupport.performIntern(SvnProgressSupport.java:109)
	at org.netbeans.modules.subversion.client.SvnProgressSupport.run(SvnProgressSupport.java:102)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)
WARNING [org.netbeans.ProxyClassLoader]: Will not load class org.tigris.subversion.svnclientadapter.javahl.AbstractJhlClientAdapter arbitrarily from one of ModuleCL@c16c2c0[org.netbeans.libs.svnClientAdapter.svnkit] and ModuleCL@2a4bd173[org.netbeans.libs.svnClientAdapter.javahl] starting from SystemClassLoader[474 modules]; see http://wiki.netbeans.org/DevFaqModuleCCE
INFO [org.netbeans.modules.subversion]: org.tigris.subversion.javahl.ClientException: svn: Cannot rename file '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/tmp/entries' to '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/entries'
org.tmatesoft.svn.core.SVNException: svn: Cannot rename file '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/tmp/entries' to '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/entries'
	at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:64)
	at org.tmatesoft.svn.core.internal.wc.SVNFileUtil.rename(SVNFileUtil.java:552)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea14.saveEntries(SVNAdminArea14.java:664)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea.modifyEntry(SVNAdminArea.java:923)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea.hasTextModifications(SVNAdminArea.java:225)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea.hasTextModifications(SVNAdminArea.java:167)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea.cleanup(SVNAdminArea.java:1012)
	at org.tmatesoft.svn.core.internal.wc.admin.SVNAdminArea.cleanup(SVNAdminArea.java:998)
	at org.tmatesoft.svn.core.wc.SVNWCClient.doCleanup(SVNWCClient.java:524)
	at org.tmatesoft.svn.core.wc.SVNWCClient.doCleanup(SVNWCClient.java:482)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.cleanup(SVNClientImpl.java:861)
Caused: org.tigris.subversion.javahl.ClientException: svn: Cannot rename file '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/tmp/entries' to '/Users/user1/Applications/tomcat/webapps/project1/nbproject/.svn/entries'
	at org.tigris.subversion.javahl.JavaHLObjectFactory.throwException(JavaHLObjectFactory.java:778)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.throwException(SVNClientImpl.java:1850)
	at org.tmatesoft.svn.core.javahl.SVNClientImpl.cleanup(SVNClientImpl.java:863)
	at org.tigris.subversion.svnclientadapter.javahl.AbstractJhlClientAdapter.cleanup(AbstractJhlClientAdapter.java:2027)
Caused: org.tigris.subversion.svnclientadapter.SVNClientException
	at org.tigris.subversion.svnclientadapter.javahl.AbstractJhlClientAdapter.cleanup(AbstractJhlClientAdapter.java:2030)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler.handle(SvnClientInvocationHandler.java:367)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler.invokeMethod(SvnClientInvocationHandler.java:331)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler$2.call(SvnClientInvocationHandler.java:179)
	at org.netbeans.modules.subversion.client.SvnClientInvocationHandler.invoke(SvnClientInvocationHandler.java:185)
	at $Proxy19.cleanup(Unknown Source)
[catch] at org.netbeans.modules.subversion.ui.cleanup.CleanupAction$1.perform(CleanupAction.java:112)
	at org.netbeans.modules.subversion.client.SvnProgressSupport.performIntern(SvnProgressSupport.java:109)
	at org.netbeans.modules.subversion.client.SvnProgressSupport.run(SvnProgressSupport.java:102)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)
INFO [org.netbeans.core.ui.focus]: External Changes Refresh on focus gain disabled

Do you get into into the state where you are forced to do a cleanup often? 
Can you run the cleanup in commandline? 'svn cleanup'? Does this succeed?

This is what I get from running 'svn cleanup' (and some ls commands) in the Terminal:

machine1:project1 user1$ svn cleanup
svn: Can't move '.svn/tmp/entries' to '.svn/entries': Operation not permitted

machine1:project1 user1$ ls -l .svn/tmp/entries
-rw-r--r--  1 user1  AD\domain users  1819 Jul  6 13:47 .svn/tmp/entries

machine1:project1 user1$ ls -l .svn/entries
-rwxr-xr-x@ 1 user1  AD\domain users  1819 Jun 17 18:48 .svn/entries

machine1:project1 user1$ ls -la@e .svn/entries
-rwxr-xr-x@ 1 user1  AD\domain users  1819 Jun 17 18:48 .svn/entries
	com.apple.FinderInfo	  32

So, it appears the file "entries" (along with a whole bunch others) were locked by the uchg flag, which makes the file immutable:

machine1:project1 user1$ ls -ldO@ .svn/entries
-rwxr-xr-x@  1 user1  AD\domain users  uchg 1819 Jul  6 14:59 .svn/entries

I had to clear that flag with:

machine1:project1 user1$ chflags nouchg .svn/entries

for a whole bunch of SVN files.

Notes: The files were copied from a Windows machine.

Then it is not NetBeans specific but rather a problem of your setup.
> Notes: The files were copied from a Windows machine.
You should probably never copy subversion metadata folders yourself (they were copied along with all other files), they are strictly in subversion competence. I myself would rather do a fresh subversion checkout to get the sources instead of simply copy them.

Yes, I agree it is more of a Subversion issue than a NetBeans issue. Thank you for your assistance.