The problem is that the same IP subnet exists on both routers' ethernet interfaces, 172.26.8.x/24. Hence, traffic arriving on either router for destinations within that subnet will be treated as local and not be routed over the serial link.
To fix this, make the serial links part of the bridge group. Traffic will then be bridged across all interfaces in the bridge group including the serial links.
One caution, broadcast traffic will also be bridged. This can reduce throughput on the serial link if the FastEthernet networks are chatty. 1% broascast traffic on a FastEthernet is 2/3 of a T1.
Try this config, note that the static routes have been removed. If you want traffic from 172.26.8.x/24 to have a default, put a static on the appropriate router (either A or B) pointing to the egress router, assuming it's on the ethernet subnet. If egress is on another interface, then you'll need to add a default on the remote router pointing to the BVI IP of the egress router.
Router A
int fa0/1
no ip address
duplex auto
bridge-group 64
int bvi64
ip address 192.168.2.2 255.255.255.0
int serial0
no ip address
bridge-group 64
bridge 64 protocol ieee
bridge 64 route ip
Router B
int fa0/1
no ip address
duplex auto
bridge-group 64
int bvi64
ip address 192.168.2.1 255.255.255.0
int serial0
no ip address
bridge-group 64
bridge 64 protocol ieee
bridge 64 route ip
