I am also getting this error.. I am also using scriptType: 'pscore' . I will make an update and report back. If pscore isn't available in a windows agent, I would think that is a bug. In my templates i use this so that it can work in both windows or linux agent pools.

edit: i know i posted this as an asnwer, if anyone feels it should be a comment to the ubuntu answer.. let me know.