Am 29.04.2016 um 11:05 schrieb Wolfgang Schuster:

You need a newer context version.

OK, that helps. Everything is fine from the command line. I seem to be overlooking something as to the setup of TeXworks, though. I copied the programme calls from the tools.ini that came with the ConTeXt standalone version into the present tools.ini that lives in my personal TeXworks config folder. Now TW starts mtxrun allright, but the run crashes with

mtxrun | unknown script 'context.lua' or 'mtx-context.lua'

Cheers -- Thomas