You may be unable to use a Cisco VPN client and IPsec at the same time in Windows XP or in Windows 2000 or in Windows Server 2003
You may be unable to use the following components at the same time in Microsoft Windows XP, in Microsoft Windows 2000, or in Microsoft Windows Server 2003 Standard Edition with Service Pack 1 (SP1):
* A Cisco virtual private network (VPN) client
* The Internet Protocol security (IPsec) implementation that is built into Windows XP, Windows 2000, and Windows Server 2003
In this situation, you cannot use a VPN tunnel to access resources on an enterprise network on which Domain and Server Isolation policies are deployed.
Refer this here