WRT54GS error 311

Hello,
I'm attempting to connect my current wired router that is hooked up to the PC to the Linksys WRT54GS router to no avail. I've tried the installation cd multiple times but every time I get to the 'check connection' part of the installation I get the Error 311 No Wired Adapter Detected. It appears that the installation disables my connection when it goes through this process thus why I get the 311 error.

Is there anyway to stop this disconnecting from happening so I can continue with the setup or will I have to manually install the router? If I do have to manually the router are there any extra steps required for going through a wired router to the wireless router?