Many have sought assistance in several forums related to their inability to establish a Windows XP incoming connection due to Routing and Remote Access Service errors, including those having Error 1003 and Event ID 7024.
The well-intended “guidance” I had found, including from Microsoft online resources, were of little value.
Best of Luck and thanks to all those who tirelessly and generously share their expertise and experience.
The Fix: Copying the two files, ias.mdb and dnary.mdb, from a working source, usually found in the windows\system32\IAS directory, from a machine that is able to establish an incoming connection, can eliminate this problem.
Proper setup of TCP/IP and NW Link IPX/SPX/NetBios services, including installation of these protocols if needed, and also including specifying appropriate network IP addresses, proper and appropriate port forwarding, as required, and unchecking the box “Use default gateway on remote network” under the Advanced TCP/IP settings’ “General” tab, can assist you to set up your VPN successfully and save you from hours – or days – of frustration and anguish.