Router stops working with Firewall SP2

I'm stumped and was hoping you could help.
I have a Windows2003 server set up as a router (RRAS) for the local LAN
IP 10.243.47.240 / 255.255.254.0
GW 10.243.46.1


I have a few routes.
Default 0.0.0.0/0.0.0.0 GW 10.243.46.1
Resource1 123.123.2.2/255.255.255.0 GW 10.243.46.29
Resource2 222.222.1.1/255.255.255.0 GW 10.243.46.29
All the metrics are the same.

My PC is pointing to this device as the default gateway.

Sometimes it works and sometimes it does not.
I can tracert to a source, everything works fine.
Wait a few minutes and do the exact trace and I get timeouts at the gateway.

So, I changed the local firewall to allow ICMP packets-All Types.

GREAT everything is working - Except now the local PC routing tables are
being updated with every site the PC has visited. What is more troublesome
is that If I change and address gateway at the router the PCs do not get the
change since the local routing table has the old value.

Any ideas?