"Project File Corrupted" means that you had working project for a while, and then screwed it up on one of the steps of your development. You got the lesson which tells you: stop doing what you are doing and setup one of the Revision Control system, to be able to retrace your steps at any point. If you don't, you don't really own your development, it really belongs not to you but to every random failure or mistake. Please see this discussion:
Revision control systems, which to choose from?[
^].
For now, if just your project file is totally lost and you cannot analyze it and fix manually (which is usually possible, but I don't have it to look at), you can always create a brand new one using your source code, which is still available, I hope. :-)
—SA