Sandisk ext'me IV 8GB cf card states 'card error' in olympus e410

I have recently purchased a Sandisk extreme IV 8GB CF card on two seperate occasions for my Olympus E-410 DSLR. On inserting card into camera it states 'card full' but no pictures on card, i then tried the format menu and attempted to format card, it then stated message ' card error'. I have challenged both sellers who firmly state that the cards are genuine and not fakes. I have also checked compatibility of card to camera on olympus websites but am confused as one states that the camera can support up to 32GB yet others state upto 8GB, my current card is the sandisk III 4GB CF card and works perfect so would like to know firstly if i can get around this error or is 8GB to much for the camera???