Ok I thought i didn't need to do luatools --generate I run it and after that I got the same error with markIV that with markII : ~/context$ texexec --lua essai.tex TeXExec | processing document 'essai.tex' TeXExec | no ctx file found TeXExec | tex processing method: context TeXExec | TeX run 1 TeXExec | writing option file essai.top TeXExec | using randomseed 764 TeXExec | tex engine: luatex TeXExec | tex format: cont-en LuaTools | running command: luatex --fmt="/home/amael3/context/tex/texmf-cache/luatex-cache/context/7280baf46d1f2412a3c85f3ce864846b/formats/cont-en" --lua="/home/amael3/context/tex/texmf-cache/luatex-cache/context/7280baf46d1f2412a3c85f3ce864846b/formats/cont-en.luc" "essai.tex" This is LuaTeX, Version beta-0.40.0-2009042222 (Web2C 7.5.7) \write18 enabled. (essai.tex ConTeXt ver: 2009.05.06 23:23 MKIV fmt: 2009.5.7 int: english/english system : essai.top loaded (essai.top) fonts : preloading latin modern fonts bodyfont : 12pt rm is loaded language : language en is active system : module simpleslides loaded (/home/amael3/texmf/tex/context/third/simple-slides/t-simpleslides.tex loading : module simpleslides system : module default loaded (/home/amael3/texmf/tex/context/third/simple-slides/simpleslides-s-default.tex simpleslides : loading default style setup color : mpcmyk color space is supported color : mpspot color space is supported color : system rgb is global activated ) system : module BigNumber loaded (/home/amael3/texmf/tex/context/third/simple-slides/simpleslides-s-BigNumber.tex simpleslides : loading Big Number style system : command NormalHeight is already defined system : command NormalWidth is already defined system : command PictureFrameHeight is already defined system : command PictureFrameWidth is already defined ) system : module default loaded (/home/amael3/texmf/tex/context/third/simple-slides/simpleslides-f-default.tex simpleslides : loading default font setup ! Illegal unit of measure (pt inserted). <to be read again> \relax l.31 ...\moduleparameter{simpleslides}{size}\relax ? If I press "enter" to continue, I get errors with fonts like this one : define font | font with name unknown is not found define font | unknown font unknown, loading aborted define font | unable to define unknown as \*24ptsstfss* [...] define font | unable to define unknown as \*30ptmmmr1ss* fonts : needs map file: original-base mplib : making 'metafun.mp' into '/home/amael3/context/tex/texmf-cache/luatex-cache/context/7280baf46d1f2412a3c85f3ce864846b/formats/cont-en-metafun.mem' mplib : problems with 'metafun.mp' from '/home/amael3/context/tex/texmf-cache/luatex-cache/context/7280baf46d1f2412a3c85f3ce864846b/formats/cont-en-metafun.mem' ][1.1] [...] mplib : making 'metafun.mp' into '/home/amael3/context/tex/texmf-cache/luatex-cache/context/7280baf46d1f2412a3c85f3ce864846b/formats/cont-en-metafun.mem' mplib : problems with 'metafun.mp' from '/home/amael3/context/tex/texmf-cache/luatex-cache/context/7280baf46d1f2412a3c85f3ce864846b/formats/cont-en-metafun.mem' [2.2] systems : end file essai at line 13 ) mkiv lua stats : used config path - /home/amael3/context/tex/texmf/web2c/texmf.cnf mkiv lua stats : used cache path - /home/amael3/context/tex/texmf-cache mkiv lua stats : input load time - 0.034 seconds mkiv lua stats : stored bytecode data - 165 modules, 42 tables, 207 chunks mkiv lua stats : cleaned up reserved nodes - 26 nodes, 9 lists of 1411 mkiv lua stats : node memory usage - 13 glue_spec, 2 dir mkiv lua stats : loaded patterns - en:us:pat:exc:2 mkiv lua stats : callbacks - direct: 202, indirect: 1349, total: 1551 mkiv lua stats : luatex banner - this is luatex, version beta-0.40.0 Might it be related to the actual bugs in beta ? best, Amaël