There are some servers where the users get put into the wrong group after the import. If that happens in your case, just let me know here or in a support ticket and we can get that taken care of for you.
Normally you should close your current forums while the import is running just to be safe.
Your other forum will continue to work after the import, just be aware that any posts or users that register after the import is finished won't be in the ubbthreads install.
Your ultimatebb.cgi script should be in the cgi-bin directory of your old ubb install.
The $URL needs to point to the full url/directory of the new install.
