General - MIDL2398 while compiling C++ application

Hi everyone!
I'm not sure this is the place for this question, but here it is:
I have a C++ application I develop with VS 2010 on windows 7.
Until 2 days ago everything went fine, and then I tried to rebuild my solusion (which includes this application and C# applications) and received the following error:
error MIDL2398: cannot execute MIDL engine

I searched it in Google, and all I could find was not relevant. they adviced to check if the file MIDC is in the same directory and of the same version as MIDL, and they are! And that was all I could find on the topic. Dose anyone know anything about this? I fill quit lost!

Thank you,
Smadar