I don't know what to tell you...
If there are no available Ethernet Type drivers it seems that Linx does not "like" what it "sees" within the TCP/UDP ports of the machine's NIC adapter; the Ethernet type driver needs Port 44818 open in "Unicast" mode and the EtheNet/IP driver needs Port 2222 in "Multicast" mode.
I'll get your IT department involved and ensure that the PC's connectivity is what it is supposed to be.
If this is not the case, then there are Registry issues with the Linx install; try deploying some extreme tool such as Windows Install Cleaner, uninstall everything related to RSLinx and then try a re-install.