Error while installing on Windows 2008 server

[faywill]

When I install the otrs-2.4.7-win-installer-2.1.1. and go to the configuration page, it comes back with HTTP Error 404.0 - Not Found.
Module: IIS Web Core
Notification: MapRequestHandler
Handler: StaticFile
Error Code: 0x80070002
Requested URL: http://localhost:80/otrs/installer.pl
Physical Path: C:\inetpub\wwwroot\otrs\installer.pl
Logon Method: Anonymous
Logon User: Anonymous

What do I need to do?

[jojo]

The Installer brings his own webserver, so you need to deactivate IIS