What size is your card? OS 4.2.2.176 supports up to a 4GB card. OS 4.2.2.196 is the latest OS for the 8830 and will support an 8GB card.
If your card matches your OS, try removing and reinstalling the card. It may not be seated properly. If that doesn't enable it to format, try formatting it in your PC with an adapter.
For more details about media card capacity, see Forum Moderator Pete6's microSD thread that's linked in my sig.