When you start IIS 5.1 on Windows XP Pro, you may receive the following error message:
“Unexpected Error 0x8ffe2740 Occurred”
The reason :
The most possible reason is if a port conflict exists on the system. By default, IIS uses port 80 for HTTP communication. If an application other than IIS or other Web Server such as Apache is running and is using port 80 on the same IP address.
To resolve this problem, you can do either of the following:
* In IIS Manager, change the port bindings for the Web site to a port other than port 80. * Stop the application that is using port 80, and then start the Web site from IIS Manager.
(from Microsoft Support)
How to view your ports: