WMA-DRM
WMA files with DRM (Digital Rights Management) cannot be converted to other formats because the files are copy-protected;
The owner of the music (e.g. an Online Music Store) does not allow you to copy or convert the music you purchase from them.
Workaround:
Burn an Audio CD in Windows Media Player from the WMA-DRM files. Then use the 'Audio CD Ripper' module of 'Easy CD-DA Extractor' to convert the music to the format you want.