First off - Searched aplenty and came up a blank - perhaps my google-fu has deserted me this morning.

I have the latest of the following installed -
CSSU
Kernel Power
ABetterCamera

Still photographs work fine, however recording video gives an empty file and no video. The screen goes black between presses of the camera button, but the recording light does not come on.
The video file is subsequently shown in the media app but no time is displayed and it does not play.

Any suggestions on debugging this issue?

Usually this relates with too much undervolting.
load stock overclocking/voltage values, reboot and see if you can record videos normally.

kernel-config load default has fixed it. thanks
had played with overcloking a while ago when testing a mythtv port and must have enabled one of the undevolt/overclock scenarios as default as it persisted though severel reboots