Hi, I have Ubb.classic 6.6 running.
And I'm wondering if anyone could tell me what the correct chmod values are for the Forum folders and the .cgi files inside it.

If I go inside my websites Cpanel and look at the error log there is a long list with similar errors: "error: file has no execute permission" and then it points to a .cgi file inside the Forum folders, or the Forum folder itself.
Everything works ok, so thats not the problem, but since this list of errors is so long, i can't see if there are any other errors on my site (it only stores the last 300 errors).
So I suspect the chmod settings on these files somehow got changed.

For the cgi-bin files, set all vars*.cgi files to 777, set all the other cgi files to 755. For the noncgi/Forum, and template, and the cache folders, set them all to 777 (and files within).

In your ubb zip file there's a help folder and inside there's a ubbclassic_test.cgi file you can upload (set to 755) and run from your cgi folder, it will check permissions and other things regarding your forum setup.