Hi Pootie proxies can be traced, but you would need a lot of co-operation between law enforcement agencies and ISPs. This could be near impossible if there is a chain of proxies and some of them are overseas.

You have stated what your main problem is:

However, he won't get banned because he doesn't post anything offensive, just those litte annoying and harrassing personal hints that he constantly posts after me.
If he won't get banned for what he posts, then nobody else will be too interested in him either.

by tracing I meant that figuring out that he is using a proxy would be enough to get him banned from that forum.
That is one for your administrators.......................