Memory card error with new memory card

That depends on the size and speed of the card(s) you choose. The A75 uses CompactFlash Type 1 cards. You don't really need a fast card.

Are you trying to load pictures onto the card using a computer? It doesn't work that way. Format the card in the camera and have fun with your new camera.

Replace the card and format it.

More likely one of the spring contacts in the camera that connect to the SD card has become weak causing the problem.

Try reformating one of the cards

It's possible a pin is bent on the connector in the camera. A good eye and a good flashlight and you may be able to confirm.

There most definitely is a solution to this problem. Follow this link for a step by step fix for the memory card error. It requires taking the camera apart but if the warranty is expired you have nothing to lose. Fix worked fine for me.

http://willj.net/2006/02/12/fixing-the-memory-card-error-on-the-canon-ixus-400s3/

Read on one site that the max size of memory stick is 128MB. I tried a 512 MB and got memory stick error. I have not ried the 128 MB yet but will this week.

Scan your card with virus program. Had same problem few weeks ago. 7 Viruses was found on card.

So as not to spoil your vacation, go buy yourself a new compact flash card locally. They should sell them anywhere electronics are sold, including WalMart, etc. See if you can get this new card to work in your camera. If so, then you can work on trying to get your current CF to work, by trying to format it in the camera. If you can't get a new CF to work in the camera, then you likely damaged either the pins in the CF socket in the camera, or some switch that is pushed when the card is inserted (to tell the camera there is a card in it). It is unlikely you will be able to have this fixed during your vacation, unfortunately.