PSP Error!!! How do I fix it?!?

I keep getting a message saying "error occured accessing file, retrying..." when I try to play Star Wars the Force Unleashed. I don't know how to make it stop other than deleting that profile and starting all over again. How can I make it stop saying that and let me play the game? Please help!

P.S. I already deleted my profile onceand it just worked until about the middle of the game then got the error.

Is this a UMD game? If so, the UMD may be bad. Another possibility is a bad memory card...any other savegame problems?

Ya its UMD...... shoot if your right I either just lost a 40$ 4gb memory stick or i lost one of my favorite games.....