help setting up synth editor in nuendo

Hi, Im having serious problems getting synth editors to work in Nuendo. to explain-
I have set up the editor so that the mido goes through the software editor to my synths (Novation Peak and Modor NF1) Im finding it difficult and keep recieving notofications that if the midi port is already open in my daw the editor cannot comment. I have however dissabled the port (marked inactive) in my studio set up. Is trhere something else I should be doing to get this to work? is there something I need to do with sysex filter?