Tetra-WebBBS Support Forum
Furthermore you still have the OLD 5.30 entry scripts in place INSIDE the NEW /bbs61x folder.
5.3x entry scripts are NOT guaranteed to work with 6.1x.
Very likely you've still screwed up things inside /cgi-bin/bbs61x.
There must be "nothing" but what exactly came with the download in exactly it's retained position. If you "copy" or "move" or "backup" any of the scriptfiles you'll end up with unpredictable results which can't be sorted out.
Please carefully check what files of which versions are in which place. There must be something mixed in where is shouldn't be.