Blackberry on read-only mode?!

Recently my memory card has been stolen out of my phone. Ok... bought a new one. I've inserted it and all apps that require accessing my media files keep saying that my memory card appears to be in a "read-only format" and that either i should choose another saving path or the app just closes on a whole. I cannot download large files such as apps with or without the memory card anymore!!! I've also tried other memory cards and still, the same thing. I've tried fixing the FAT, still nothing. How can i fix this?