type ':script' to see what all scripts it's loading, and then check any of those for anything odd.
Especially make sure that any needed dependencies are loaded. For example, the .vim files under .../syntax/ directory. As to which ones are needed for what, I couldn't really tell you. It seems like my vim has always loaded all the appropriate scripts, on it's own, just fine. Anyway, that gives you something to check out and investigate.
If that doesn't help, then the next thing you could do is 'vim --version'. This will give alot of information about the modules and options your vim was compiled with.
This may be a stupid question, but are you naming the file with the proper extension? AFAIK, vim doesn't know how to properly highlight, until the file being worked on, has a filename extension that it is familiar with. That is also providing that the necessary script(s) have been loaded up, which is one of the reasons I make mention of looking at the output of ':script'.
Last edited by PingFloyd; 11-18-2006 at 10:13 AM.