I was messing with my command library and got this error. Was also messing with verbs and types. Got ahead of myself and got this error. Can't remember what I did.

Any ideas where to look?

Error running script: Error compiling expression "Outstanding actions: " + Join(this.actions,",")': FunctionCallElement: Could find not function 'Join(object,String)' 

No matter what I do the error comes after first move in the game The game still runs as well so im thinking it is not the library but something I did in Quest

Find that line in your code. I assume there's something in your game that should display "Outstanding actions:" ?

It looks like this.actions is an object, not a stringlist. (Or, more likely, is an unset attribute. Because that counts as null, whose type is object).
If you can't figure out why this.actions doesn't exist, maybe you could share the code with us? Or provide a link to the game so we can take a look?

thanks mrangel. Found it, fixed it
Had to do with the NPC library.