I found a migration issue when switching from cvs-plugin 1.6 to 2.x.
The regular cvs client support checking out all files readonly to facilitate cvs edit/unedit and watchers, apparently this is not supported by the netbeans cvsclient.

If a job was checked out with the old version of the plugin (1.x), updating the workspace fails due to
java.io.FileNotFoundException: some_filename (Permission denied)

This is not a big issue since the file permissions can be changed with find, nevertheless maybe it is possible to change the file handling to change write permissions before trying to overwrite the files.