My small home network is hidden behind an RT314 firewall.

Do you have ICMP blocked? you have to configure ICMP on the router to
block incoming with a rule netgear excluded it in there last
rt314 firmware ( I had 4 netgear routers myself) the IP address
probing you likely belongs to a victim who was hacked and not
the attackers so reporting to abuse is a complete waste of your
time no Cracker will use there real Ip because he/she knows they will
get caught and traced right away unless the Intruder is a lamer
script kiddie who doesn't know better You can install my
netwatchman to automaticly forward probe and attack
reports from your router to the proper people www.mynetwatchman.com
another suggestion: when your not home or away you can disconnect
your pc from the Internet really reduces the risk.