mp3hot2, check microSD slot working properly ( 2240 is not new device, the contacts could be oxidized ). Format card in Fat32, insert it in nuvi and connect nuvi to PC. Does PC recognize the card ? If not try to remove and re-insert the card 3-5 times.
I think correct path for map on card is /Map/anyname.img or /Garmin/gmapsupp.img