My opinion?
If you ever hack your board again, I will hurt you.
Okay... first off, whoever told you to nuke the .cgi files is probably right on.
Delete the cp_* files, the ubb_* files, the vars_* files, cp.cgi and ultimatebb.cgi.
Delete your Templates directory.
Delete anything in your Members directory that isn't a directory or a file ending in .cgi.
Make a clean, fresh, new install straight from the 6.1.0.2 zip file.
Make sure the Members directory has the member_test.cgi file and the last_number.cgi file.
Make sure all the files that the zip has in the noncgi directory really are there.
That should avoid the cp.cgi login loop.
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Charles Capps
Programmer, Infopop Corporation
Please do not contact me privately for support - post on the board or open a support ticket instead!