I was getting the page cannot be displayed/found error like many other individuals here on Windows Server 2003. I forgot that Windows Server 2003 comes with .NET 1.1 and installed 2.0 via Windows Update. After uninstalling and reinstalling .NET 2.0 I continued to get the error. I decided to uninstall .NET 2.0, but this ended up leaving me with .NET 1.1 issues. I then found the following KB article from MS on repairing .NET 1.1 on Windows Server 2003.
http://support.microsoft.com/kb/830646/
I followed the steps under Manually repair the .NET Framework v1.1 - I hope that this helps many of you with the Page cannot be displayed/found error on Windows Server 2003.
P.S. - I am tempted to install .NET Framework v2.0 via Windows update to see if the error returns. I will think about it and keep you updated...
Update: Installed .NET Framework v2.0 via the Redistributable Package and not Windows Update and everything still works!