The link that doeseas provided is dead...so I don't know what he tried before.
Here's the text of my original post:
Open up a terminal window (command line) and type:
ls -l /etc/mtab
The result should look something like:
12 Jun 11 22:15 /etc/mtab -> /proc/mounts
If it doesn't have the arrow pointing to /proc/mounts (and my guess is that it doesn't), then it got turned into a real file somehow and remembers a time when you did not have those cards mounted.
If it did get turned into a file (arrow part is missing), su to root (assuming a 3.10 ROM; otherwise you're already root under 2.x), then type the following:
rm -f /etc/mtab
ln -s /proc/mounts /etc/mtab
If the arrow part was there to start with, then I'm afraid I can't help you.