File Upload Field works in Tropo, not in Twilio

I mentioned this in my email, but posting it here for posterity.

My initial configuration of the module was using Twilio. The number/textfield and select components worked fine right off the bat. However, the filefield/voice recording field is having an issue. During the call, the system prompts me for input, but after I press the pound key to finish recording, I'm greeted with a system error message: "We are sorry. An application error has occurred. Goodbye."

I checked to make sure the file field allowed the 'mp3' as a valid file extension. It does. The same issue happens whether the field is set mandatory or not.

I decided to try Tropo to see what would happen, and changing the configuration to Tropo causes it to work properly.

This is perhaps a bug in the voiptwilio.module, but I'm reporting it here until that can be determined.