Unfortunately, you're not alone with the problem you're having with your memory card. There's a discussion on the same subject which you should find helpful.
http://www.digicamhelp.com/cgi-bin/yabb/YaBB.cgi?board=access;action=display;num=1096138468;start=0There are several suggested solutions posted there which have helped others and, hopefully, will help you. Yesterday, for example, a board participant named Ken Cunningham wrote of how he fixed the problem. His post is on page four of the thread.
If none of the suggestions work, I highly recommend you contact the memory card manufacturer. Or maybe bring the card back to the store where you bought it, bring along your digital camera too, and test out some others in the store.