It sounds like AME is not remembering its settings, or they are corrupt.
Two things to try:
1. Open AME from the Start menu. “Restore” it so that it is not “Maximized” and then move it a little so that its position is changed. Close AME and try exporting from PPro and see if AME pops up in its last position.
2. If the above does not work, delete the AME preference file. AME will re-create it next time it runs.
Cheers
Eddie