There were a few hiccups and it may be the propagation hasn't completed yet. I've done the same thing (dns flush) and was getting the old forum as well.
I can't access my profile section...
I can get on the forum with no problem on my mobile phone.
But I cant get on it on my laptop.
I just get a message about moving servers when I try on my laptop
Your laptop is accessing the site on the old server. Try flushing your dns. To do this open a command prompt by clicking start and typing cmd in the search program and files box.
Then in the command line window type
then hit return.