can’t access admin – don’t have permission?

Hi I tried to install bbpress forum on my site, went through all the setup etc etc … it didn’t workout – it says its installed yet it has errors when i visit the url i installed it in. So I put that to the side for another day… however now when i login to my blog i can’t access the admin area – it says “You do not have sufficient permissions to access this page.” i was trying to link the bbpress forum with the login with my blog so all i can think is something i stuffed up somewhere, can anybody help me??
i am running the latest version – i would click that option but i jsut installed IE 8 and its preventing me to show drop down lists claiming they are popups… #@$$@#@$@