- What version of MB are you using? Help > About
- Is that the complete error?
- Try looking at the error log Help > Support > View Error Log and see if there are any entries around the time that error occurs. If so, copy/paste the lines here.
- Is there any commonality about when the error occurs? And if you try playing the same song again, does it throw the error again?
- Make sure the music files are not marked Read Only.
- Are you running an AV program? Might it be Avast? If so, whitelist MB and see what happens.