TiVo working through router(working as switch) but no WIFI

Hi guys! I'm new to this forum but I come here in the hope that you can help me figure out why is it that when I connect my TiVo to my linksys router(configured as a switch), I STOP HAVING WIFI! Don't know why... As soon as I turn the TiVo box off the wifi starts working(as soon as I reboot the router)... The TiVo works perfectly, no breaks and perfectly connected to the network, but that specific router switch where it is connected, stops functioning though wifi(can't even connect!)

The setup I wish to use(and that is currently working) is:

Modem router(Thomson)---through cable to another router(with dhcp and nat disabled)airporttime capsule)--- through cable to another router(linksys) also with dhcp and nat disabled... Everything works when not using the TiVo box...
The only switch that stops working is the linksys(the one to which the tivo is connected)


Help me pleAseeee
(I'm from Portugal-using an internet tv service)