This bug was originally marked as duplicate of bug 157005, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE 7.3 Beta 2 (Build 201211062253)
VM: Java HotSpot(TM) 64-Bit Server VM, 20.12-b01-434, Java(TM) SE Runtime Environment, 1.6.0_37-b06-434-11M3909
OS: Mac OS X
Created attachment 131190 [details]
Help ID "debug.jpda.attach" is not available.
It's probably missing in the usersguide module.
Reassigning. Ken, can you please evaluate it? Thanks.
I'm very sorry, wrong bug, reassigning back.
I'm sorry, I cannot reproduce the bug. It seems that the files were deleted
externally right before they were read.
Closing for now. Please reopen if you can provide steps to reproduce or other
additional information. Thanks.