MiKTeX LuaLaTeX broken, probably font-related problems [closed]

When I updated my MiKTeX installation (on Windows 7) today, LuaLaTeX went broken. When I try this minimal example it compiles with PdfLatex and XeLaTeX but not LuaLaTeX:

\documentclass[12pt]{article}
\begin{document}
Hello world!
\end{document}


I get this error message:

If I understand it correctly, the main error message is about a syntax error in a luaotfload script? And I guess that it tries to print another error message about some missing font or something?

From fontspec throwing error with lualatex - broken? i tried the command

luaotfload-tool --update


which gave me a similar error message:

A similar problem (fontspec throwing error with lualatex - broken?) was related to a missing lmodern font package. But I cannot find that package in MiKTeX Console. I have installed similar packages (lm, lm-math, variablelm) but that does not help.

I still guess that the problem is related to the Latin Modern font somehow, because in directory C:\Users...\AppData\Local\MiKTeX\2.9\luatex-cache\generic\fonts\otl, where the font cache is, the font listing goes alphabetically and stops at lmsans10-regular.luc.

Any ideas?

Edit:

If I continue the compilation process by hitting Enter, LuaLaTeX gives a new error message, which maybe can spot the actual problem:

• Your error shows pathes related to ...ograms\MiKTeX 2.9\scripts. This doesn't sound like a single user installation. If you run a small document with luatex (not lualatex) which contains \directlua{tex.print(lua.version)}\bye what do get as output? – Ulrike Fischer May 1 at 12:39