Hi,
Yes, this is generally true. All modules should get loaded before \starttext.
Well, I had loaded it before \starttext in both cases. But when I loaded it in the first line of my file, it didn't adjust the delimiters; after moving the \usemodule[nath] line directly above the \starttext line, it worked like a charm. Maybe I produced some garbage inbetween. :-)
However, the units module still isn't working when nath is loaded. Is it supposed to?
[...] Anyway, it looks like the fix is easy: the problem is that dimension commands are not protected (unexpandable).
[...]
Thank you very much, I'll try that. If it doesn't work, I can still get along without units, though it would have been nice to have that too. BTW, is there some kind of manual on aligning nath equations? I tried to align multiline equations using \startalign, but that only worked (in display mode) as long as no delimiters were used; \[ \startalign a &= (b \\ b &= c) \stopalign \] always produced an error message saying that I had left out an "}". I probably made some mistake, so a tutorial on aligning equations with nath would be great. The nathguide.pdf mentions eqnarray, but I guess that's not available in ConTeXt, or is it? Best regards, Sebastian