am using nero 7 ultra edition to burn music, all do my MP3s can be add to the burn list but my WMA files cant. it wont add, everytime i try to add it pop up a caution message saying "one or more files can not be added to a compilation". so i used a WMA to MP3 conversion program and it still wont let me add the WMA files to be convert to MP3. can anyone help? thx in advance.