I guess I am missing something in my font handling here, but do not know what.

Hans van der Meer

This is the minimal example:
\def\fontname{antykwa}
\setupbodyfont[\fontname]
\starttext
Requested font = \fontname.\crlf
\showbodyfont
\stoptext

This is my setup with respect to fonts:
context/tex/texmf-fonts (link to /usr/local/textlive/2011/texmf-dist/fonts

Executed: mtxrun --script fonts --reload
Executed: mtxrun --script fonts --list --name antykwa
giving as output:
antykwatorunskaregular   antykwatorunskaregular   AntykwaTorunska-Regular.otf

Below is the output of the minimal example. Mark that \showbodyfont names modern, not antykwa. I get the same result with other fonts mentioned in "fonts in context" page 69-71 as preloaded typescripts! 

For example calling typeface cambria it even gives an error:
! Math error: parameter \Umathquad\displaystyle is not set.

system          > tex > error on line 6 in file test.tex: Math error: parameter \Umathquad\displaystyle is not set ...

1     \def\fontname{cambria}
2     \setupbodyfont[\fontname]
3     \starttext
4     Requested font = \fontname.\crlf
5     \showbodyfont
6 >>  \stoptext
7     

\doshowbodyfont ...mr \languageparameter \c!text $
                                                  \quad }\vrule }\cr \noalig...
<to be read again> 
                   \stoptext