Are you on ps3? if so, try heading to the psn store and activate the dlc maps again, to do this just hit download on each map, it will say "activating" after that just cancel the download and your maps will work again
you will need to do this every time after datatransferring =)
what modded patch are you using? it could have something to do with the eboot or viceversa the modded save game =)
hope this kinda helped lol