LuaScriptEngineFactory not found / Attempt to index ? a null value

[hexadecimal-chocolate]

I'm making a plugin for another java application in which I have no control over when my jar is loaded.

For some reason when starting, this message pops up in the console:
ScriptEngineManager providers.next(): javax.script.ScriptEngineFactory: Provider org.luaj.vm2.script.LuaScriptEngineFactory not found
It seems to load the META-INF/services of luaj without loading the classes.

I'm not sure if it's related, but when I run this line:
globals.load(new Bit32Lib());
I get this error:
Caused by: org.luaj.vm2.LuaError: attempt to index ? (a nil value) at org.luaj.vm2.LuaValue.error(Unknown Source) at org.luaj.vm2.LuaValue.indexerror(Unknown Source) at org.luaj.vm2.LuaValue.gettable(Unknown Source) at org.luaj.vm2.LuaValue.get(Unknown Source) at org.luaj.vm2.lib.Bit32Lib.call(Unknown Source) at org.luaj.vm2.LuaValue.load(Unknown Source)
This error occurs when loading any of the default libraries except BaseLib.