Your mission is fine. Something is wrong with your system. Try reinstalling all the software from C:\Program Files (x86)\Steam\steamapps\common\il-2 sturmovik cliffs of dover\redist again.
Check game files integrity.
If it does not help, install a 2nd copy of Win7-64 and install only steam and the game into it. No other software. It may help. You are the only one who experiences this strange problem.
Try downloading and running other missions from here
http://forum.1cpublishing.eu/showthread.php?t=21602
and here
http://forum.1cpublishing.eu/forumdisplay.php?f=203
If nothing helps you can also start a mission in a dedicated server and join it as a client from the same PC if you have 4gb+ RAM. Read this forum section for instructions on dedi server.