Just converted one of Anders’ songs to AIFF using Audacity - signed 16bit fidelity. Plays in WMP just fine, but when importing into Content Pipeline, it comes in as an invalid/unsupported content file. So…AIFF’s off the table.
Tried again with WAV, same export settings as the other song - 24bit fidelity, 44.1KHz, straight from his DAW. I used one of his other songs from the Retro Grooves album to confirm that it wasn’t just Dreams Inc failing on me…and sure enough…
Guess the Content Pipeline hates The 8-bit Guy as well. 
Edit: I FIGURED IT OUT.
So, AIFF’s not supported. I began to try various settings in Audacity to export the song as a WAV. First, I tried 32-bit float. Same error as above. I then tried 24-bit signed PCM. Same error.
I then tried 16-bit PCM and BAM! It worked perfectly. Of course, this may lose quality but I doubt anyone but audiophiles will care. The good thing is, we figured it out.