Not sure if it is firmware or not? (2 replies)

I have just finished building a printer and it is working fine except for one issue.
When I plug in the thermistor for the heatbed I get this error message scrolling continuously;

Error:
: Extruder switched off. MINTEMP triggered !
Error:Printer halted. kill() called !!
Error:
: Extruder switched off. MINTEMP triggered !
Error:Printer halted. kill() called !!

The thermistor is the same type as used in the hotend, both are 100K
I tried swapping the hotend for the heatbed and also the thermistors too, and I still get the same error message, so I guess that the settings in the firmware may be at fault??

It seems strange that the error message refers to the extruder.

Any help would be appreciated.

PS: I have tried a few Printrboards (revD) and they all do the same with my setup.