I believe I am experiencing the same issue and wondered if this has been resolved.
I have a class that has a bunch of strings in it that pass to and from jint when I run a script so the script will have access to those variables. I recently added a List<string> variable to the class (csharp code) and tried to access it
via js only to get an error.
I was not sure if the syntax was correct but the previous posting seems to state I am on the right path.
string result = jintEngine.Run("return Variables.string1"); - this is OK
string result = jintEngine.Run("return Variables.list"); - this does NOT work
Am I approaching this correctly?