This is a Tulip clone, which is listed in tulip.c, and
according to Linksys' webpage worked in RedHat 6.0.
The PCI identifier of the one I have is VID=0x11AD
You could try using the driver disk available at:
Boot the installer with 'linux dd', and use that disk
when asked for a driver disk.
Does that help?
This issue has been assigned to a developer for further action.
Try out the latest installer available in beta and tell me whether we have
gotten it right this time.