[knc1]

Then that is probably a report BY reader.lua could not find something it needed.
Although that is a bit strange, Lua usually have very good error messages (and a stack back-trace).

Read the reader.lua file (it is human readable, only compiled at runtime) and check for things listed in a 'require' statement not being present.
You will have to check against the search paths used by the Lua that is being executed (Lua has its own search paths compiled in).