Comping error suddenly developed?

Hi, for some reason when ever i try to recompile a project, even a clean project build im getting this error:

Error 180 error C3861: 'Path': identifier not found D:\Torque3D-master\Engine\source\sfx\sfxProfile.cpp 245


Why would this be, i have been compiling previously and ive never had this error?

Im using VS2010 express.

Thanks
Andy