I am facing the same problem on my windows phone .Message says - Storage card not work, Your storage card has changed,is damaged,or non-complaint. To fix this turn off ur phone or replace it with a new complaint card.Then you'll need to reset ur phone to original factory settings. To reset ur phone refer to the owner's manual." and i can make an emergency call or turn off.
I tried restart , reformat to factory setting and all ,it didn't work.
I am not using any external SD card. I am using in built phone memory that came originally with phone.
I had a similar error happen once on the Focus I had. It was with the external card. I had pulled the card and placed back in but that didn't fix it...but it seemed to clear after a couple of restarts/battery pulls and has been fine since.