4GB Lexar Premium 60 switch is up, but the message I get says

If it is an SD or SDHC memory card the answer is yes.

You might have locked memory card. If not first try to connect memory card to PC with memory card reader and try to copy your stuff... then after you take all stuff try to format it.

SD and SDHC cards have a slide switch along one edge. The position farthest from the contacts locks the card, protecting it from writes. The position nearest the contacts unlocks the card. If the switch is already in the proper position, slide it fully the other way and then back again.

see if their might be some photos or file saved that you may have edited on the card maybe Microsoft visual studio's photo shop save to hard drive. delete with photo software and format put in camera format again. if it works with computer and not with the camera not compatible try another card

Go to this link and follow the instructions to update your camera's firmware to be compatible with High Capacity memory cards.
http://www.fujifilm.com/products/digital/download/a820_a825/fupd.html

All SD (and SDHC) cards have a locking switch on them and this can be activated accidentally when handling the SD card.

Remove the SD card and slide the switch on it away from the lock position. If this does not work or if the switch is already in the correct position, then slide it all the way to lock and then fully back again.

If this fails then you have a faulty SD card and must replace it. Dirty electrical contacts do not result in a card locked message so you won't have to worry about those but as with all memory cards never touch the contacts unless they clearly need cleaning. Note that if you have to replace the memory card you can use regular SD cards up to 4GB and SDHC cards which start at 4Gb rising to 16GB maximum. The camera slows down when using SDHC above 8GB though.

I hope that you have found my answer to be of use and in return I ask only that you rate my answer.

First of all, the 4GB card will never be able to work in your camera. Check on its face. It likely says SDHC, and SDHC cards as this format came out after your camera was designed (I know it looks exactly like a normal SD card, but it's not).

Now the 2GB card should work with your camera as it is a standard SD card. Remove the card from your camera. Look on the side of the card for the tiny slide switch, and slide it to the other "unlocked" position. Reinsert it in the camera, and see if that corrects the problem.

check again as mine has one. it is tiny so you may not have seen it easily.

If it is one of those without then have you formatted the card so that yo computer can see it properly

unlock your card. you'll get that message when the SD card is locked.  Lock the card only to prevent deleting photos from it. good luck!
Alberto

The switch goes fully forward for unlocked and fully back (away from the contacts) to lock it.