I've had that issue in the past with my Droid too. Certain forums simply won't open. Usually the problem goes away on its own in a few days from my experience but its annoying in the meantime. Certain threads I've been unable to reply to as well through the app.
It's great to see an entire section dedicated to "support" yet apparently numerous people have the same technical issue and there has been no resolution or even much attention given from the admins. SUPER psyched that this will cost us money for faulty forums!