More problems!

For what reasons could the Error light on Sabertooth come on? The manual says Thermal cut out or Over Current but neither of these are an issue.
I just re-wired the whole robot thinking it was some dodgy soldering causing a short but the light still stays on. Furthermore when the error first came about, if I wiggled the power wires going to the Sabertooth (before the re-wire) the light went off. And now after spending a few hours trying to sort the problem my Brushless ESC has started making error tones.

It's all quite bizarre. The voltage reading at the power distributor is 12.3v and I recently charged the battery. If I wiggle the throttle stick the Brushless ESC comes to life, but the motor barely turns (actually appears to shudder backwards and forwards). Really quite stumped so any ideas would be much appreciated.

Thanks,

PJ