It's not cpanel.cgi you need to worry about, it's UltBB.setup. Replacing either will not help. In fact, replacing UltBB.setup will probably make things worse. <img src="https://www.ubbcentral.com/boards/images/graemlins/smile.gif" alt="" />
If UltBB.setup lacks a "1;" at the bottom, put one there and upload a copy of it in ASCII to your UBB's CGI directory, then reset permissions on it. That should kickstart things into working again.
If you continue to get errors after that, you'll probably want to open up a
support ticket so an Infopop tech can examine and resolve the problem.