I just reset all settings from the camera, and CHDK. I then set the TV override to 30 seconds, and took a picture. Shutter was <1 second.
What are the actual settings you entered in the "extra photo operations" menu?
What Canon shooting mode is the camera in (M, Tv, some special scene mode, etc)?
What does the override display (in red in the upper left) show?
Did you wait press half shoot long enough for the camera to pre-focus?
Is an external flash attached?