I guess you're using the "Call by reference" node then. This is only possible if you open the VI reference with a type specifier.
If you want to do this, then all the VIs that you're going to call dynamically must have exactly the same connector (matching the type specifier connector).
If this is not the case you either have to make all connectors the same or you can't use "Call by reference".
You can still call your VIs dynamically using the methods "Set control value" and "Run VI".
Daniel