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