Does your ethernet led burn green? Ifso you should be able to check your dhcp clients table and find the ip of the last client or search for the macaddress, then you can check if it's there with your browser. Finding extenders using the pronto pro software didn't work here either, I just added the extenders with there id's on the systemspage properties. On my rfx 9600 the 0 id seemed broken, when putting the id from 1 to 0 the id remained 1. When putting it from 1 to 2 it changed. So I'm using 1 a.t.m.

If you have a router or gateway please tell the important parameters (skip the wireless settings because the pronto is already connected). Mine as a sample:
DHCP Server: Enabled
Max DHCP Clients: 50

I need to know your setup, as an example mine is on the bottom of this post, please write down yours. Any connection inside a device is left to right, external connection are top to bottom. So Motorola SURFboard SB5120 UTP is Connected to Router Wan and Router Lan is connected to the switch. a.a.a.a is always the same (123.124.125.126) b.b.b. is always the same (192.168.1.) x is a changing number.

Motorola SURFboard SB5120 Coax (Cablemodem, DHCP Client, a.a.a.a)	Motorola SURFboard SB5120 UTP (Cablemodem, DHCP Server, a.a.a.a)
	Linksys WRT54G Wan (Router, DHCP Client, a.a.a.a)	Linksys WRT54G Lan (Router, DHCP Server, b.b.b.x)	Linksys WRT54G WLAN (Router, DHCP Server, b.b.b.x)
		Linksys EG005W (Switch)	TSU9600 (Pronto, DHCP Client, b.b.b.x)
		PC & RFX9600 (DHCP Client, b.b.b.x)