[NTG-context] latest beta hates most of my fonts

the latest beta refuses to work with most of my (Greek) fonts. I have compiled the very latest trunk (rev. 1006, I think). Difficult to make a minimal example because it doesn't happen with simple "Latin" text, only when there's Greek in the file. The error message is always similar: ) Fatal error occurred, no output PDF file produced! Does that ring a bell, or should I see if I can find a font which doesn't work in "normal" mode? The fonts are set up like this: \installfontfeature[otf][grbl] \definefontfeature [agreek] [mode=node,language=dflt,script=latn,kern=yes,tlig=yes,trep=yes, grbl=yes,featurefile=greek-babel.fea] \definefontsynonym [Serif] [name:BosporosU] [features=agreek] etc. Thomas