Memory Card Error

This error message means that the card is corrupted or formatted for another digital camera. Turn off the camera. Insert a new card or format the card.
Try to format the memmory card using a card reader and the PC this should solve your problem if not you have to replace the memmory card.

i think you have a faulty card. get a cotton swab and clean the golden contacts over the memory card. If problem pertains then get a new memory card.

Did you format the card in the camera before trying to use it?

I think the largest card you can use is a 4G SD card.

you may try some card recovery software, recommended asoftech photo recovery that helped me before.
http://www.asoftech.com/apr/

If needed, you may do a quick format of the card, and then use asoftech photo recovery to recover files.

This is a known issue.  Check out the Canon Support site: http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=223&modelid=8777&keycode=2112&id=27465

Buy and format a new memory card

I think the problem may bethat you are using a 4Gb card. The manual says not to use a card larger than 2Gb.

We have the same problem. Seems to be a common problem.

I've had similar problem when I was messing around with the Sony memory stick. The cheap pins inside that suppose to touch the memory got screwed up. I just bought the camera so took it back to the store and got a different one. Anyway, try shining a flashlight into the memory slot and see how the pins are. If they are not line up then use a really small something to re-line them like they suppose to. See if it's possible to reformat the memory. That sometime help too. It happened to my sis cell phone. We had to reformat the memory stick to get it working right. I do not think this have anything to do with battery. If you don't put memory in and camera say "No memory" and with memory in and it read "Mem error" then likely the reader or the pins are screwed up. Goodluck.