I also encountered this problem, but with another level - the first one you play as the Rebels. I rescued the guy I was supposed to rescue, completed all my objectives, got him into the evac shuttle and then...nothing. It just sat there. I loaded up my last saved game and got to the same point, and the same thing happened again.
You're not going to like this, but the only way I could get past this little glitch was to restart the entire level back from the beginning ie. click on 'continue' at the start up screen rather than 'load saved game', and go through the briefing and hangar bay again. It was incredibly annoying, but when I did this I encountered no problems and was able to progress as normal.
"Life. Don't talk to me about life." (Marvin the paranoid android).