One point.. The nsrck command in NetWorker 5 rarely catches index errors. nsrck -F will compress and fix, but I wouldn't trust the nsrck on startup too much. As an alternative, I used a script that would do a small nsrinfo on each client.. We found quite a few more bad indexes that way..
Also, NetWorker 6 uses a different client indexing scheme, that appears to be a lot more reliable.
Good luck!!