For future reference if you cant fix the problem by that method, the problem might just be with the .RVPROJ file. if it is, it'll be fixed by doing this:
1) Open notepad
2) Type "RPGVX 1.NN" (without the quotes)
3) Replace NN with the version of RMVX you have. If you don't know which version you have just put 00
4) Go File>Save as and under the 'save as type' section choose 'All Files'
5) In the 'File Name' box put "Game.RVPROJ" (WITH the quotes)
7) Replace the game.rvproj with your corrupted project's file