repair directory of lite-on dvd recorder?

I have a LITE-ON LVW-5045 DVD Recorder with the 160 HD. This machine occasionally locks up when i'm editing programs on the HD and the only way out is to unplug it. Of course, when you do this there's always the danger of losing everthing and, after getting away with it many times, that's what finally happened. Over 100 hours of programing and work gone. The Browser would still show all the programs with names, dates, time, length, etc. but no thumbnails. And if you tried to view the files it would try but no go. Is there anyway to get these files back?
DVD's work fine. And i have temporarily replaced the 160 HD with a 40 GB drive.
Thanks for any help or suggestions.
Keith.