If you have a problem opening a corrupted CorelDraw project in X5, you should first try to extract its RiffData file. At a basic level, CDR14 and CDR15 files function like Zip archives, so you should try to open the project with WinZip, then access the RiffData file. It should contain the layers of the initial project, which you may then visualize in X5, and work on them accordingly.