Probably you are using latest patch 1.17.5. Its not official one i guess, because you cant find it here
http://www.menofwargame.com/mow/updates.phtml
Try reinstall the game,then install only patch from the official site and problem should be fixed. It helped me with some other mission bug, and it can help u too.
The problem is that u cannot use savegame from 1.17.5 in 1.11.3 so u'll have to play again this mission.