Kodak 4 GB SD card (brand new) shows "card error" in Pentax optio

The S6 works with SD cards. Your 4GB card is actually an SDHC card and will not work with your camera. You need to use SD cards, 2GB and smaller.

Sorry. The 550 works with MMC and SD cards. While SDHC cards fit into the slot, they are electronically incompatible and will not work in this camera. You need to go with MMC or SD cards, 2GB and smaller.

No. The S40 works with SD cards, not with SDHC cards. You have to use SD cards, 2GB and smaller.

Did you format the card in the camera before using it?

Have you tried formatting the card in the camera first?

You need to format a new card in the camera.

The S5z is limited to SD cards, 2GB and smaller.

The maximum supported memory for Pentax Optio 430 is 256mb and for Pentax Optio 430 RS is 512mb.

Check this site for more information.

Optio 430
http://www.upgradecomputermemory.com/ram.cfm//memory/P/Pentax/Pentax-Optio-430/

Optio 430 RS
http://www.upgradecomputermemory.com/ram.cfm/memory/P/Pentax/Pentax-Optio-430RS/

The sd card is to big go for a 2gb ted10

The maximum supported size is most likely 2GB SD Card. Cards with 4GB and more are following a new (incompatible) standard called SDHC (SD High Capacity), SDHC cards work only in devices specifically supporting SDHC. The Optio S5N uses the old SD standard where 2GB are the maximum size.