java.lang.NullPointerException
   at org.netbeans.modules.ade.client.FilesCommand.computeRelativePaths(FilesCommand.java:21)
   at org.netbeans.modules.ade.client.FilesCommand.addFileArguments(FilesCommand.java:31)
   at org.netbeans.modules.ade.client.CheckoutCommand.prepareCommand(CheckoutCommand.java:62)
   at org.netbeans.modules.ade.client.ADECommand.getStringCommand(ADECommand.java:156)
   at org.netbeans.modules.ade.client.ADEClient$CommandRunnable.handleCommandError(ADEClient.java:230)
   at org.netbeans.modules.ade.client.ADEClient$CommandRunnable.run(ADEClient.java:201)
   at org.netbeans.modules.ade.client.ADEClient.execImpl(ADEClient.java:161)
   at org.netbeans.modules.ade.client.ADEClient.access$000(ADEClient.java:37)
   at org.netbeans.modules.ade.client.ADEClient$1.perform(ADEClient.java:119)
   at org.netbeans.modules.ade.util.ProgressSupport.run(ProgressSupport.java:106)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1454)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2036)