I think I've managed to set ConTeXt to mkiv, things proceed relatively smoothly, and from the log file, it appears that the right files are read. I'm using the most recent version of Schusters's letter package.

When compiling the example letter, the following error occurs:

! Undefined control sequence.
<argument> \@@@@lsoptionmethod 
                               

the macro in question seems to appear in default.nli but is not defined anywhere.

Any and all help appreciated. 

Thank you,
-- 
Rolf Marvin Bøe Lindgren
+47 40061755