Hey,
This is what I got when searched a little for your log:
"When a replicated packet is sent to the software by an output ACL, the hardware does not indicate whether the packet needs to be bridged or routed.
When resources are exhausted or when the ACLs programmed in the hardware cannot handle processing directly (such as ACLs matching TCP flags), the Supervisor Engine III sends the packets to software for processing. If the software cannot make the determination, the packet may be dropped. This drop indicates that the packet was directed to a Hot Standby Routing Protocol (HSRP) router group MAC address."
For better understanding kindly post 'show ip arp (ip of the source}' and 'show ip arp (ip address of the hsrp group)'. Also post the brief topological overview of the arrangements of source, destination and hsrp inbetween.
--gaurav