I've found two ways of clearing the Kodak Zi8 SD Card Exclamation Point error status.
1. Unlock the SD Card
2. Remove all files from the SD card via your computer file manager
This third option was suggested to me but I did not need to try it.
3. Format the card while it's in the Kodak Zi8.
I tried this, but the Zi8 came back with a Red Exclamation Point, so I ended up using option 1 on one card and option 2 on another. Both worked.
What has worked for you?
Update from Kodak:
"It is likely that they are lower speed cards - we recommend class 6 but can use class 4"