I don't know what version of WMP you are using, I am using Version 10. There is a checkbox in the tools/options/rip music settings box that has to do with protection. If that box was checked when you ripped the CD's the resulting WMA's could be copy protected on your hard drive. Other than that I am not sure what it would be. Hoster is pretty straight forward. I did notice that the WMA's that I tried to import that would not play had some astronomical number in the duration field.
gpayne