Here's a thought,if you have RRAS running on your server check that the NAT/Basic Firewall component is NOT enabled. If this setting is enabled it will prevent Windows Firewall from working. This component of RRAS uses the Ipnat.sys file to function.
If you have 2 NICs scenarios that the NAT is enabled on the SBS 2003 server external NIC in RRAS (or ISA). The NAT driver (Ipnat.sys) provides the network address translation function. It is used by RRAS and Windows Firewall (or ICS). However,
once you enable the NAT in the RRAS, the Ipnat.sys will be occupied and Windows Firewall cannot start properly. That explains the error message " Windows firewall cannot run because another program or service is running that might use the network
address translation component" (Ipnat.sys)".