First switch off the tablet, and then drop the battery off for 30 seconds. Put it on again and turn it on. Has the problem solved?
If not, is possible that the filesystem in the cards is damaged.
Open xterm, become root, and check the cards:
fsck.vfat /dev/mmcblk0p1
fsck.vfat /dev/mmcblk1p1
That should fix them. Reboot and they should be mounted again.
In the worst case you may have to reformat them, loosing your data.