VISA 0xBFFF0011 (insufficient location information or resource not present) with ICS Electronics 8065 LAN to GPIB gateway

Hi, this problem has me pretty much completely stumped. Any ideas or guidance is very welcome.

My hardware:

ICS Electronics model 8065 LAN GPIB gateway (pdf spec sheet)

connected to:

ICS Electronics model 4863B GPIB/IEEE488 Bus interface (pdf spec sheet).

My software version:

Labview Version 2012 SP1

Measurement & Automation Explorer Version 5.4.0f0

NI-VISA Version 5.3

Problem description:

When I try to connect to the VXI-11 interface of the 8065 from NI-MAX, I get the error:

Error opening resource: 
TCPIP0::172.21.2.160::gpib0,4::INSTR

VISA:  (Hex 0xBFFF0011) Insufficient location information or the device or resource is not present in the system.

 Steps to reproduce:

1.  In  NI Measurement & Automation Explorer -> Devices and Interfaces -> Network Devices, choose "Add Network Device", "VISA TCP/IP Resource"
2.  Choose "Manual Entry of LAN Instrument"
3.  Enter IP Address (172.21.2.160) and LAN Device name (gpib0,4)
4.  Press "Validate" and immediately get the above error.

Troubleshooting steps taken

Pinging the instrument:

Successful

Connecting to instrument with telnet to port 111

Successful

Connecting with 3rd party VXI-11 utility

Using "ICS Electronics VXI-11 Keyboard" Can successfully connect and run "*idn?"

Connecting from another computer:

From a different computer, running LabVIEW 6.1 with MAX v3.1.1, if I follow the exact same steps as above, I can connect and talk to the device (e.g. write "*IDN?\n" to the device and read response with the VISA Basic I/O utility).

Running wireshark

I can't see any packets sent or received to the device's IP address using wireshark, which I find odd.