As a workaround -- just to get the project DONE -- I'd render out of the AE Render Queue in a lossless codec, then bring the rendered file into AME.
Read on Reddit that you reinstalled Media Encoder and you got your export working. Glad to hear it.
For anyone else who can't see reddit...
Sometimes this problem happens to me if one of my apps was updated and the other was not. The dynamic linking seems to stop working if you have a version mismatch. Make sure your AE, PRE and AME are all updated to the most current versions then they should play better together.