Strange Situation

Hi
My standalone Lumatron DVD24 player suddenly decided to play copied dvd movies only, and not the originals. It played the same originals just fine some time back, but not now. I copy on good Fuji cdr’s and the copies of the same movies play perfectly.
It just doesnt load the originals anymore the way it does the copies.

Please help me with playing my original movies again.
Thanks

Are your discs scratched, dirty etc.?