If you encounter the message “Playback error” in Windows, while using Tunebite to convert protected filer then apply this solution to solve the problem.
All you’ve to do is to play the audio or video filers in the original media player – e.g. WMA and WMV in Windows Media Player or M4V, M4P, and .aa files in iTunes.
By playing the files in the original media player the DRM license is automatically downloaded to your PC and you’re now able to utilize Tunebite to remove it from the files in question.