I think iproute meant, could you post your configs?
What do the serial interfaces show (interface and line protocol up or down)? One suggestion: if your T1 is not running through a public network, this means there is no source of timing for the CSU's/DSU's. Try setting up your CSU's/DSU's in a master/slave configuration, ie your master CSU provides clocking to the slave, and both CSU's then provide clocking to the routers.