get lualatex working

Hello,

I have miktex 2.9 portable, on windows zp. Texstudio compiles everything I need with latex/pdflatex/xelatex but cannot get lualatex starting. My D:\tex\miktex\miktex\bin folder is in the path and here is the conf:
http://i.imgur.com/NfKGaBx.png
with the error

Process started: "D:/tex/miktex/miktex/bin/lualatex.exe" -synctex=1 -interaction=nonstopmode "reprep".tex

Error: Command crashed: "D:/tex/miktex/miktex/bin/lualatex.exe" -synctex=1 -interaction=nonstopmode "reprep".tex

Process exited with error(s)

when I compile a doc:

\documentclass[twoside,a4paper,12pt]{article}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

Test
\end{document}



When I go to the options of miktex, and try to build lualatex, I get



Creating the lualatex format file...
Running miktex-luatex.exe...
miktex-makefmt: miktex-luatex.exe failed on lualatex.ini.
initexmf.EXE: The operation failed for some reason.
initexmf.EXE: Data: D:\tex\miktex\miktex\bin\miktex-makefmt.exe




idem for luatex.



kind regards
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