Thread:Extension talk:Scribunto/Lua error: Internal error: The interpreter exited with status 126./reply (9)

If they have lua 5.1 installed (e.g. as /usr/bin/lua or /usr/bin/lua5.1), you could set $wgScribuntoEngineConf['luastandalone']['luaPath'] to point to that to still be able to use Scribunto. But yeah, that's unfortunate.