Unity 4.0.1f2 update and script,fbx file errors,.

For a few days Unity 4.0.1f2 update was working flawlessly and i have downloaded some assets from store.Yesterday Unity asked me again to upgrade my project for new version on a little message box.After that system begun to give errors for fbx files and under scripts(special scripts,mouselook.cs,charactermotor.js,fpsinputcontroller.js ...etc.).Now i am loading my project backup but i can't compile the previous one due to errors.