Which browser are you using, Arby?
I've just checked in Chrome (exact same version on OS X) and I'm having no trouble staying connected in chat or in the forums. However, I think that was my first time signing in with Chrome on this computer, so I didn't have anything stored.
Does it do the same in Incognito mode?
Another thing to try if you have a second user account or Guest login available is to see whether you can use the same net connection, computer and Chrome install to access the site as another user - which would point to it being a local setting or file.
R