Route add in XP for ethernet

[Hunter quest]

Re: http://www.computerhope.com/routehlp.htm

I have two computers. They both connect to a wireless router. I want them to connect via ethernet for local files. That's fine...but the laptop repeatedly prefers the wireless to send to the other computer. This is slow. Hence a route add to indicate which connection to use.

For the NICs I have specified,
Laptop - 120.120.120.120
Desktop - 120.120.120.121

Default gateway is 192.168.0.1

I've tried this myself and I get "the route addition failed...interface address wrong or gateway wrong, mask parameter invalid" ...et cetera.

Go ahead, explain this.

[Hunter quest]

Crickets...what about this? Adding something to LMHOSTS. Or is that the same as what I am trying to do in the command prompt?

It's just irritating. Occasionally the ethernet will get the job of moving a file, but mostly the wireless, which takes four times as long.

There must be some networking expert here; someone wrote that page. 

"route add 120.120.120.121 mask 255.255.255.0 192.168.0.2 metric 1"
(The route addition failed: The specified mask parameter is invalid. <Destination & Mask> != Destination.)

192.168.0.2 is the wireless client (laptop's) IP. I also tried 120.120.120.120 (assigned NIC's IP), 192.168.0.1 (default gateway to router). I'm sorry I'm not clever enough to do this...