Bindery – NDS printer conversion in Citr

I am in the process of changing all of my Netware 4.0 printer/objects/queues to NDS from Bindery mode. Citrix Metaframe 1.8 via Terminal Server 4.0 accesses these printers through Gateway Services to Netware. One of my applications (not Microsoft) gets an error “Unable to open port” when the user tries to print to that NDS printer. Bindery printers work fine. The application itself runs from the Netware server as there is a SQL database that runs on it. I am also trying to convert all users to NDS connections (they were originally created via a Bindery utility.) I am not sure if the problem is how Citrix passes the information across, or whether it is the user’s gateway access that is causing the error. Any ideas? Thanks