Cannot exit Mako on Asteroid X57 in Bring Down the Sky

Bought the Mass Effect trilogy via Origin recently. My character is at Level 49 now on first playthrough and could not exit Mako on X57 asteroid for the Bring Down the Sky dlc that came with the trilogy. Tried keeping vehicle still and on level ground and at different areas of the asteroid, but kept having the standard message if I want to go back to Normandy whenever I try to exit Mako using holster button. Tried all other buttons too and still could not exit. No problem with exiting Mako on other planets. Using Windows 7 64bit but running game on compatibility mode of Windows XP. Please help!! Thanks!!