[nsp] Why does'nt this config work?

[Kevin]

BTW, thanks for the help with BGP question everything works as expected
now :)

Here's the setup:

FE-- 3640 -----PtP T1------- 2501 ---E--
          -----PtP T1------- 2501 ---E--
          -----PtP T1------- 2501 ---E--

3640 is running 11.2(21)P
3640 config:

!
Bridge irb
Bridge 1 protocol ieee
   Bridge 1 route ip
!
Interface FastEthernet 1/0
	ip address y.y.y.253
!
Interface Serial 2/0
	no ip address
      bridge-group1
!
Interface Serial 2/1
	no ip address
      bridge-group1
!
Interface Serial 2/2
	no ip address
      bridge-group1
!
Interface BVI1
      ip address x.x.x.254 255.255.255.0
      ip helper-address y.y.y.y

2501s are running 11.2(17)
2501 config:

!
Ethernet 0
	ip address x.x.x.253 255.255.255.0
	bridge-group 1
!
Serial 0
	ip unumbered ethernet 0
      bridge-group 1
!
Bridge 1 protocol ieee
!

I can't ping x.x.x.254 from any of the 2501s and I can't ping it from a
machine behind a 2501, although I can ping the 2501 from a machine.
Is there another way I can do this? Or is my config just wrong? I beat
my head against the wall trying to figure this one out :(

Kevin,