Dave-So,What you described is a very common problem with CD-RW type disks. While there is only one standard for burning to a CD-R disk,there are about five for CD-RW.This depends on the make of the CD drive,and not the brand of computer,or CD burning softwear used(like two different model computers from the same company may have two different CD drives,made by separate makers). Add to this the very nature of CD-RW disk make them easy to become corrupt. Don't know if this is what happen to you,but people should be aware to use only CD-R disk(not CD-RW),when archiving important info(like Poser files). SWAMP