I find it interesting that such a script would require PHP to have safe mode off to work properly. Usually th problem with safe mode is that it restricts uploading files. But that is irrelevent here. Must be something to do with permissions and how the author of that script set things up. Anyway, not to harp on about it but that is strange that for the purpose of the scripts, safe mode matters.
Anyway, what this guy is suggesting is to run the scripts as CGI rather than through the the php module loaded into Apache. For this to work, your web host needs to have a php binary available problably somewhere such as /usr/local/bin/php
To run the scripts as cgi (and assuming your host supports cgi) you would change the file extension from *.php to *.cgi
Next, in each of the scripts you would add a line to the very begining of the script which tells the shell where to find the binary to process the script. So each of your scripts will end up looking like
You would use the path to the php binary as given by your host.
May I also say, that what you want to do is actually quite easy using php. (without all this mucking about with CGI too). If you are keen to learn php and mysql - this would be a good first project. In fact, forwarding/redirection scripts have been discussed often in the past. you could do an advanced search of the forums and you would get some code and ideas. As a hint, on shared virtual hosting accounts this can be done a couple of ways - either by using ReWrite Rules in a .htaccess file (if your host has mod_rewrite installed and you are allowed to over-ride using .htaccess). Or, a simple kludge is to use a script inside a 404 Error Document that does the redirection. Some of the scripts out their use the 404 Error Doc trick - such as http://www.go2cgi.com/cgi-bin/go.pl?/phpredirect/
As for good sites for beginners, look at the link in my signature for Skunk's list. Good luck.