hmm...it could be easyer if you just move your main site (the .com one seems like it) over to your board site (which seems like the .net one) and make it so it's like
www.mysite.com/forums or something......or if you had PHP on your main site, then you could of done an include statement accross sea

but it seems like it doesn't have PHP...so I don't know what to tell you

I'm sorry