Hmm, tough one to figure through here. What is the file type, source and location on the computer. Can the program actually handle the file, do you need admin rights to access it. I could ask a lot more questions here.
My tip. Log on to the Magix Website, give them the exact details, and get them to reconstruct it, cos' that's what you really need to do. A serious error can cover a multitude of sins.