You do not have a version of the FogBugz database that FogBugz could read.  It is possible that restarting your web server will reset things back to normal.  If you are trying to get FogBugz to create a blank database for you, please add a table named Version with a column named ixVersion (int) and the value 0 in it.

Please backup your data and reinstall FogBugz.