Originally posted by kiwi_jono +1 , I have had problems too.
I wish they would sell the cards with fixed tabs as I have never used the write protection tab personally.
Cards can get corrupted when put into a card-reader without write-protect being set. In this case, the computer may add information to the card, invisible to the user, that prevents the camera writing to it. Whenever I put a card into the card-reader, I
always set write-protect - it is possible that this how the OP's card became corrupted in the first place.