never ever seen that before, try rebuilding bitfields to see if that helps any, yourforum/admincp/index.php?do=buildbitfields you can disable plugin's in your config file
goto your vbuetin files where it says do not upload there is a script there i believe its tool.php i forget been a while since i used it and run that it should fix your bitfiles and datastore.
i think some trouble with vbcredit