Am 12.03.2014 um 15:51 schrieb Lars Huttar <lars_huttar@sil.org>:

This gets rid of the error, but it seems to prevent any expansion of the
content of \CurrentUser, because the page head now literally looks like
this:

You can try to print the string in verbatim mode:

\def\CurrentUser{\cldcommand{sprint(tex.vrbcatcodes,os.resultof"whoami")}}

\def\Markname{Compiled \date by \CurrentUser\ \LUATEX +\ConTeXt\ \contextversion.}

Wolfgang