Prior to the .NET Framework version 2.0, applications could register a component to handle FTP requests using System.Net’s extensible pluggable protocol framework.  Components for handling different web requests are registered by associating the component with a specific URI prefix.  Any web request that matches that prefix would then be handled by that component.  In version 2.0 of the .NET Framework, System.Net now supports an FtpWebRequest component that is registered by default for the “ftp:” prefix.  Any applications that are registering for this prefix (prior to this release) could now be broken because the prefix (FTP) is already taken.

 

There is a workaround for this issue.  It is as follows:

 

Update the application configuration file to remove the default FTP pluggable protocol prior to registering your own FTP component:

<system.net>

<webRequestModules>

<remove prefix = “ftp:” />

                        </webRequestModules>

            </system.net>

 

 

I hope this information helps to make your applications transition to Whidbey smooth as silk :).