perhaps a stupid question, but are you on a PC (i.e. not Mac)? if so, have you tried the simple drag & drop in Windows? (or copy & paste the VIDEO_TS folder from the burned DVD to a destination on your hard drive.) often that method will work and make perfectly fine error-free copies when ripping software (e.g. DVDDecrypter) has problems. just another thought.

also, i second AAR.oner's recommendation to make sure your LiteOn drive's firmware is up-to-date. with media changing a bit (to accomodate for DVD drives with faster burning speeds), it's sometimes crucial to have updated firmware to be able to burn certain media using certain burners.