Card error even with no card inserted

Can be lots of things. Would have been handy, if you had told what card you are using. Your camera can work with CompactFlash, Microdrive and xD-Picture cards.
If you did not insert the card(s) you are using, correct, or you removed the card in a wrong way, you could have damaged the cardholder, causing an error you probably can't repair yourself. The CF and Microdrive you can remove by pressing the eject button. The xD-Picture card you can remove by pressing in the card, and release it. The card comes out.
Then you could have damaged the file system, by opening the card cover, while the card access lamp was blinking. What ever card was in, the filesystem can be damaged.
Then you can have two cards in, Both, o CF of Microdrive and a xD picture card. Some settings are required for the camera, to know hat card it should use.
If you have an Microdrive, the drive can be damaged, by a magnetic file, or the drive just stopped rotating. A micro drive is actual a miniature spinning hard drive.

First check if the memory card is inserted correct. Eventually, remove it and check all contacts, on the card and in the camera. Then try formatting the card. If you think there could be important pictures on the card, put it in a external card reader and use a recovery program, to see you can recover the pictures on your computer. Programs can be found on the net.
If you can't format the card, check if you have a Microdrive. If so, try to replace that with a CF or xD card.
I hope something is to any use for you.

Next time, please give us some more details. I know you exactly see and know what is not working, but we only can use your description. And only what you give us.

Your 2gb xd card would be of the "M" or "H" designation, which is a new type of card which is not always compatible with many cameras and card readers. If the other cards that work are not H or M cards, that is most likely the problem

error 99 can most times be remedied by taking a standard pencil eraser and carefully cleaning the gold contacts at the back of the lens and the gold maching contacts in the lens opening of the camera... BE CAREFUL not to let eraser crumbs into your camera... keep it clean... reset the battery and give it a whirl.... did it solve the 99 issue?
for the CF it refers to the cf card... here's what I've found on this:
Canon reports that this error code may appear on your digital camera’s LCD (liquid-crystal display) when there is an error reading from or writing to the inserted CF (CompactFlash) card. This error code occurs most often after a user has tried to eject a CF card before the camera has finished writing data to the card.Solution:
Canon suggests that you first try to use a different CF card. If you do not see the error message when you use the new CF card, the first card is probably damaged.

Before you take the next step, drag the files from the CF card to a location on your hard drive to back up the files. Next, you can use Windows’ ScanDisk utility to check the CF card for errors. If you use a Mac, you can use Disk Utility (in Applications\Utilities\) in OS X.

If ScanDisk or Disk Utility fails to resolve the CF card problem, insert the CF card in your camera again. Then format the CF card. On most Canon cameras, you can do this by pressing the Menu button, selecting the Format tab, highlighting Format, selecting Format, and choosing Yes. Make sure you have backed up the data on the card before you do this. Formatting the card will delete the images from the card. After you format the card in your camera, use ScanDisk or Disk Utility to check the CF card again. If you still encounter errors while using ScanDisk or Disk Utility, you should discard the CF card because it is damaged.

If the error still occurs after following the steps above, your camera may need repair. Contact Canon’s technical support for further assistance.

hope this solves your issues....
let me know
K

Try to clean contacts with 70% alcohol and q-tip.

First things first - need to make sure that the card is making proper electrical contact with the camera. Have a look at the contacts at the edge of the card and make sure they are spotlessly clean - even a fingerprint may cause problems.

Also, make sure the contacts in the camera have nothing causing a contact problem, and see if this resolves the issue.

Regards, Andy

check the pins in your cf slot.. you may have one bent. either straighten it out or send to repair

Not know the age of the card, is seems that it is faulty and needs to be replaced.

when XD card is inserted printer says "card error"

Have you tried formatting these cards in your camera? You will find the setting in the menu as per page 26 of the manual. Also check that the correct card type is set for xD or CF as appropriate. You can download the manual from the link below: http://www.olympusamerica.com/files/EVOLT%20E-500%20Advanced%20Manual.pdf Please update the question & let us know if the information given was useful to you - Good Luck!

Nikons and Fujis keep the CF slot powered, and "poll" it every now and then to see if a card has been removed or inserted. So yes, a camera may drain batteries much faster with a CF card than it does with an XD. But if it really does do this, then someone at Fuji deserves to be on the street, looking for a new job. Polling a card every few seconds does not have to be a traumatic experience to the camera. A Nikon can sleep for months, and not show appreciable battery drain. After what I've seen in the horribly slow CF write times of the S3, and the large artificial difference in write times between CF and xD on that camera, I'd say someone (or several "someones") at Fuji is doing everything in their power to make CF look bad and steer people into xD.