Agent Unable to Register on Login

I just downloaded the new version of Second Life. After starting it up and enetering the world, I flew into the air and went forward. After flying forward for a while I tried to turn, but I was unable to. I couldnt do anything but go forward. I even flew off world and still couldn't stop. Since I couldn't do anything I went to File and then Quit. When I started up the game again, it froze while trying to 'register agent.' I went to the control panel and ended the task and tried it again to the same effect. What do I do now? Thanks for any help!