|No, IEEE1394 is your firewire adapter. If you don't use it, or you don't actually have a working firewire port then I'd recommend just disabling and ignoring it.|
The only problem the OP appears to have is that the new modem/router supports WPA2, whereas the old one was only WEP and WPA. Obviously Verizon, in their wisdom, have set up the other computers to use WPA2 as it is supposed to be more secure, but the older network adapter does not support it, even with the latest drivers, which are still old. Hence installing a new adapter which will support WPA2 will solve the connection problems. Also WPA is easier to set up that WEP which is also probably why Verizon went down that route.
"I've always been mad, I know I've been mad, like the most of us..." Pink Floyd