You should drag the crew from a tank to another and drop them, if you are running windows vista make sure to run as administrator, because otherwise the games has lots of problems
Yomust also create your profile when you are running as administrator
So run as administrator, create a new profile and then you can save as normal but remember you must always run as administrator
You are most likely playing on windows Vista
to be able to Save you must run the game as administrator
right click the EXE file or the EXE file shortcut on the desktop and select run as administrator