i'd like to post a Bug. At the moment you can't use strings as out parameters. I think OPC_AssignStrDrop fails. The statement pointer shows to the wrong memory. The "new" string at sp[-2] is wrong. Could that be?? I debugged a little and i think sp[-3] would be the right pointer.
This calls the the output Method:
27: Offset mTestStr
28: VCall String_Output 2
And now the Receiving Method:
1: PushString"Output String"
I think the the OPC_LocalValue1 opcode increments the out parameter. So that AssignStrDrop fails. The same code should work if String_Ouput is native, but i don't have tested it.