Did you close it manually yet? There should be a crank rod in the trunk with the tool kit. Just pop of the lens for the rear passinger dome light and there should be a place to insert the crank. crank it home and.... bingo! closed sunroof. This may also free up the jammed part.
sounds like a problem i had on a mazda 929 that i had a while back. one of the cables broke, and it wouldn't retract correctly. the dealer wanted about $1200 to repair it and i found a guy parting out his 929 and bought his m/r assembly for $80. it probally took me about 5 hrs to replace it on a sat afternoon. not sure if it's your problem but i hope it helps. :dunno: