This is the best news of the day .So I was in the same boat you are in. Nothing could read the card except for my Nokia n97 mini. It recognized the card as "locked" and prompted for a password. I bypassed the prompt and went to the file manager. From there it let me format the card and it is back to normal. See, Symbian is good for something after all!
PS: I tried the same process with an E71 and had the same successful results. All recent Symbian phones should work as it appears they can handle the encryption and password. The card is now happily back in my HTC EVO.