Like DynaMight said, make sure the swap file is off. You could also try "umount -f /media/mmc1" or "umount -f /dev/mmcblk0p1"

Also, type into xTerm "df" and hit enter. It should display the free space on your mounted partitions (And by extension the partitions currently mounted).
Do you see "/dev/mmcblk0p1" there or anything with the words "mmcblk"? If not the card isn't mounted...