FL Studio is being gay.

Okay, so I imported this .mid file into FL Studio... I changed the  instrument that was used for the main channel, then tried exporting it into MP3 format. When I open it, it's a 22 minute long MP3, that has no audio. Anyone know how I would fix this?

yes, there is only one way to fix this problem: use a real audio program like Logic, newfag.

Check the MIDI when you import it. If it imports tracks that are not used, such as drums, that can happen.