mville...I am unaware of your relationship with the the support ticket process that you are responding to. My conversation up to this point has been with "Spoon", and while I do appreciate your willingness to help, I can't help but feel that the logical approach here is to deal exclusively with "Spoon".
However, for the sake of clarification, I performed the following tests:
(1) completely uninstalled BitDefender (including all previous personal settings) and tested the problem. The 0 Byte MP3 file creation problem was unaffected.
(2) prior to reinstalling Bitdefender, I booted into safe mode and retested. MP3 files were created successfully.
(3) I reinstalled BitDefender, then rebooted into safe mode and retested. MP3 files were created successfully.