Lantronix XPORT connection difficulty

6 months ago, after much fiddling, we were successfully communicating with the XPORT device over TCP/IP with operating systems WinXP and Win7. That is no longer the case. Now, we seem to connect, but after a delay of several seconds we get an ascii string before the connection is then disconnected.
The ascii string on the Win7 OS is: “Port is out of range” or “Undefined MTYPE command”, depending on the machine or using API or not API.
The ascii string on the WinXP OS is: “HTTP/1.1 0 ERROR”
Is there something we need to check in the NCD tool to see if for some reason the device is no longer configured properly?