The following example produces expected output with MKII (texexec) but fails the compilation process with MKIV (context). \startuseMPgraphic{foo} input graph; path p; gdata("data.d", $, augment.p($1,$2);); draw begingraph(4in,2.5in); gdraw p; endgraph; \stopuseMPgraphic \starttext \useMPgraphic{foo} \stoptext The data stored in data.d is as follows: 0 0 1 1 2 4 When compiling with MKIV, the following error occurs: !mplib : mp terminal: (/opt/context-minimals/tex/texmf/metapost/base/graph.mp ! Redundant equation. <to be read again> ; l.143 Gmargin.low=-.07; % bbox fraction for default ra... ! Redundant equation. <to be read again> ; l.144 Gmargin.high=1.07; % bbox fraction for default ra... ) !mplib : mp error: unknown, no error, terminal or log messages !mplib : mp terminal: [1] !mplib : mp error: unknown, no error, terminal or log messages -- Troy Henderson