Rouring and Remote access + Comodo Firewall 4.1 = problems

I have a computer running WinXP SP3 with 3 network interfaces. First one is a physicall link to ISP’s network. I have a connection to ISP’s intranet by it. Second interface is a connection to ISP’s VPN I’m linked to Internet by. Third one is a TAP connection to my VPN built on OpenVPN. OpenVPN server works on the same computer. NAT is also established on this computer for providing an access to ISP’s intranet to clients in my VPN. Here is a NAT settings:

C:\WINDOWS\system32>netsh routing ip nat show interface

NAT Local Area Connection Configuration

Mode : Address and Port Translation

NAT OpenVPN TAP Configuration

Mode : Private Interface

Network security is provided with Comodo Firewall 4.1. Connection to ISP’s VPN is brought up by autoexnt.bat script that’s called on system boot by AutoExNT system service from Windows Server 2003 Resource Kit. This make it possible to connect to my VPN from Internet without logging in any local user on this computer. Here is a command from autoexnt.bat that sets connection to ISP’s VPN up:

rasdial ISPVPN loginname password

I have a problem when both Comodo Firewall and “Routing and Remote access” system service is working. In this case connection to ISP’s VPN isn’t set up on boot. But if I try to bring it up after system boot manually I haven’t any errors. System service of WinXP built in firewall also doesn’t start automatically but starts manually without problems. I need this service to be launched because nobody can connect to my VPN otherwise. It’s impossible even ping me without this service if “Routing and Remote Access” is started. There is no errors or somthing like that in system event logs or Comodo Firewall log. Problem disappears if I entirely turn off Comodo Firewall (turn off services, rename driver files and reboot system). As well as if I turn off “Routing and remote access” system service (but in this case NAT doesn’t work). What’s wrong?