Amit,
How did you determine that the traffic is not arriving on the FWSM?
On the switch:
sh run | i firewall (does this include the vlan in question?)
sh vlan id (does this show the vlan is in the database?)
On the FWSM:
sh vlan (includes the vlan in question?)
Have you configured the vlan interface on the fwsm?
-Kureli
