I'm going to install MRTG on my server following this FAQ:
http://secure.xprowler.com/mrtg.htm

but my server is CPanel, not Ensim. On that page, it lists a file to copy and paste depending the version of ensim that you are running, http://secure.xprowler.com/mrtg.txt or http://secure.xprowler.com/mrtg31.txt .

Which should I use for my CPanel server?

- Matt

Use the ensim 3.1 text file, it will work fine for cpanel. We have it successfully setup on 4 cpanel servers.