I can’t get the example in the m-barcodes module to work. I have no urgent need to print barcodes; I was just curious. I'm writing in case I found an easily corrected bug.
The release notes from 2010.05.08 call this module mkiv only. But according to the log, the file m-pstricks.mkii is used. And that seems to be the proximate cause of the error.
mjg
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ConTeXt ver: 2010.06.23 12:45 MKIV fmt: 2010.7.6 int: english/english
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command: context "barcode-test.tex"
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file: barcode-test.tex
\usemodule[barcodes]
\starttext
% this is copied straight from m-barcodes.mkiv
\startPSTRICKS
\pspicture(-4mm,-1mm)(38mm,26mm)
\psbarcode{9781860742712}{includetext guardwhitespace}{ean13}%
\endpspicture
\stopPSTRICKS
\stoptext
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log before the error:
systems : begin file barcode-test-pstricks-0001 at line 1
system : module pstric loaded
(/context/tex/texmf-context/tex/context/base/m-pstricks.tex
(/context/tex/texmf-context/tex/context/base/m-pstricks.mkii
! I can't find file `multido'.
<argument> \input multido
\relax \input pstricks \relax \input pst-plot \rel...
\firstoftwoarguments #1#2->#1
l.47 ...s}{using indirect method; enable write18}}