Don't worry. I've had the same problem. (or at least it looks very similar)
You probably updated your HW44 AK2i card with the new firmware. But you didn't update your Akaio to the latest version then.
My card didn't show up either.
When I updated my Akaio to the latest version, my card showed up, but it still didn't work.
So try updating to the latest Akaio. If that fixes it, great. If that doesn't fix it, you're out of luck. You'll have to wait for a newer firmware to get your card to work on your 3DS.
In the meantime, you can fix your card by running the firmware 141 update on a DS lite. After running that, it should work on your DSi again. But it won't work on your 3DS.
If this doesn't fix your problem, then congratulations, you either have a fake Acekard, or you're the very first person in the world with a really bricked Acekard 2i (what I seriously doubt)
Edit: Read the 20+ pages topic about the AK update, it lists all the possible links/solutions etc...
edit2: For the truly lazy, here are the download links:
http://www.acekard.com/download/ak2/
http://www.acekard.com/download/ak2/ak2ifw_update_141x.zip