I can understand you not wanting to take your originals with you. It's a good idea to take your "backups" with you when using your Panasonic portable while your originals are safely stored at Netflix, ehem, I mean your closet.

Do prerecorded DVDs fail too? if so, you have a defective player. If not, there might be some kind of read cashing incompatibility. Try a different portable in that case.