Trouble Exporting to Media Encoder

I am working through the online educator course for Character Design and Animation, and I've already hit a snag on my first assignment.  I recorded something, and everything went as the instructions said it would until I tried to export to the media encoder.  It says "could not read from source. check settings and try again."  I am not familiar with either Character Animator or Media Encoder, so I have no idea what to do if the instructions don't work.  I'm working on a Windows computer, if that helps at all.

Help?