First, make sure the Ethernet cable is a crossover cable, or an ethernet hub with a standard category 5 cable, and that the Tascam's ethernet lights are: one flashing and one solid while the computer is on. The computer's lights vary by ethernet card manufacturer.
Set the IP address of your PC (right-click on Network Neighborhood, go to Properties, find your ethernet card's TCP/IP settings, double-click, and go to the IP Address tab. Select Specify IP, and type in:
IP Address: 192.168.100.2
Subnet Mask: 255.255.255.0

The computer will require a reboot if you have changed these settings.

If Viewnet simply doesn't open, make sure you have the latest Java version, as of 11/06/01, it is version 1.3.1. If you need a newer version, go to sun.com to get the newest Java.

On your MX2424, go to menu #950 (Press setup, #9, then "up" or "down") for it's IP address.
Set the IP address to 192.168.100.001
Then go to menu #951 (Press setup, #9, then "up" or "down") for it's "net mask".
Set the mask to 255.255.255.0

The Tascam does not require a reboot, simply exit from the menu.