Batch preprocessing problem - Couldn't execute this instance in the global conte

[blinky]

I'm getting this error when running the script:
Couldn't execute this instance in the global context.
Reason: No master calibration frames or overscan regions have been specified.

I have added FLAT and LIGHT frames, checked a refrence, left the use master flat/dark etc unticked but when I hit run I get the above  -  what am I doing wrong?

[astropixel]

I think the script/Calibration module requires as a minimum a bias or dark frame.

[blinky]

Ah, that explains it then!  I will try and take some BIAS frames tonight then!