1. Check the security tab on each of the SD cards. If the switch is set to protected mode then the card is locked. Make sure the SD card is not locked and try it again.

2. If you are also using a non-supported SD card this may cause the H2 to misread other cards. Try reinserting the included SD card and power the H2 on/off several times. This may clear the error caused by the unconfirmed card and allow the included card to be seen again. This may take as many as 10 times and you may need to leave the unit powered off for 24 hours to completly clear this error.

Check the following link below for a list of approved H2 SD cards.
Zoom H2 approved SD Card List