I've searched the forums but haven't found anything relevant specifically this this issue, so I'm attempting a new post.
I just got into Marley, and when i got on the Balloon Car, my client hadn't fully downloaded the place I was going to. When the download completed, I was still stuck in the Balloon Car, I couldn't go anywhere else.
When you finished downloading, you should have 'arrived' at your destination. Were you able to exit the game, reenter and end up at the other side or are you still unable to reach your destination?