coopee,
Is your device still displaying an error code, or did it go away after you upgraded the firmware to C9? Error code 89 was a common error with the GPIB-ENET/100 which is why we released the C9 firmware. I would imagine that if you haven't seen an error code since you upgraded the firmware that you actually saw error 89. If you are still seeing an error code verify that it is indeed 8 long pulses, and 8 short pulses.
As far as your EDVR issue and sequentially verified failing. Is your GPIB-ENET/100 configured with DHCP, or a static IP address? Since you have two ENET/100s, and one is working, check to see if there is any difference in how they are configured. Are they both configured with DHCP or static? Are they both on the same subnet as your computer?
I suspect like Scott suggested that you are experiencing a networking issue.
Shawn B.
National Instruments