There are situations that might have caused this error:
The mobile phone doesn't have support for the SD card you want to use which in this case you need to update the software on the BlackBerry
The SD card you want to use is actually corrupted. Attach it to a card reader then format it on the PC.
Official list for supported SD cards based on the software of the device:
BlackBerry Device Software 4.2.0 Up to 2 GB
BlackBerry Device Software 4.2.1 Up to 4 GB
BlackBerry Device Software 4.2.2 Up to 4 GB
BlackBerry Device Software 4.2.2.196 Up to 8 GB per Verizon Release Notes and confirmed by users.
BlackBerry Device Software 4.3.0 Up to 8 GB
BlackBerry Device Software 4.5.0 Up to 8 GB
BlackBerry Device Software 4.5.0.81 and later Up to 16 GB
BlackBerry Device Software 4.6.0 and later Up to 32 GB