Can't Print Thru Port Server II on a VPN

I have a Port Server II 16 port device. Part number 50000309-04 S. It is a remote device. Mainframe is at host site. The port server connects to a switch whcih goes into a router, which connects my WAN via frame relay. When this connection is live all works well with the port server, no issues at all. My mainframe is an RS6000 runing AIX 5.3.

When my frame relay connection goes down, my DSL backup connection is established. It tunnels through my PIX at the host site. When this connection is established all dumb terminal devices connect up to the host mainframe fine and all works very well. Howerver, the printers I have attached to the Digi Port Server do not print. Anytime I send a print job to them, nothing happens. AIX gives an error message on the printer as DEV_BUSY. Any ideas on this???

Is the RealPort driver being used on the AIX host?

When the VPN link is up, telnet to the Portserver II and issue the “who” command from the root prompt and post the results.