Flash Media Server (FMS) and Microsoft Internet Information Services (IIS) cannot use port 80 on the same IP address.  

Solution

Assign a separate IP address for Flash Media Server and Internet Information Services so that they can both use port 80.

1. Disable socket pooling so that you can enable additional IP addresses on the server.
2. Follow the instructions from Microsoft KB Article 238131: How to Disable Socket Pooling.
3. Prevent IIS from binding to all IP addresses on the server. For, IIS 6 use the httpcfg.exe tool to assign the IP addresses for IIS. Follow the instructions in Microsoft KB article 813368 to use the httpcfg.exe tool.
4. Bind the Flash Media Server adaptor to an IP address. Flash Media Server binds to port 1935 on any IP address by default. IP addresses in Flash Media Server are configured in a file called the Adaptor.xml. The adaptor.xml file is in the Flash Media Server root \conf\_defaultRoot_ folder. 
   
   In the Adaptor.xml, find the <HostPort> tag.  Include the IP address that you want Flash Media Server to bind with. For example, "127.0.0.1:1935,80,443" binds to the IP address of 127.0.0.1 on ports 1935, 80, and 443. Save the file and restart Flash Media Server and IIS. You can now run Flash Media Server and IIS on the same machine.

Additional information

When you start Internet Information Services (IIS) 6.0 on Microsoft Windows Server 2003, IIS binds to all IP addresses on the server. Flash Media Server and IIS can't listen to port 80 on the same IP address at the same time.  

This solution is for Internet Information Services (IIS) version 6.0 on Microsoft Windows Server 2003.