The easiest way to test to see if your provider has PHP enabled, and what version is to create a text file containing:
Save it as phpinfo.php, upload and execute. This will tell you if PHP is enabled, the version, and the configuration of PHP.
Safe Mode is NOT the cause of the error from earlier in the topic. The problem is the open_basedir restrictions prevent ultimatebb.php from seeing the cgi-bin directory because they are not in the same directory.
If you are getting 404 errors, and the PHP isn't even parsing, then your host has some problems with their server. 404 implies that the file has been moved/deleted. If you see that Whoops! Message that is in the comments at the beginning of ultimatebb.php, then your provider either has PHP disabled, or not correctly installed.
