We just bought a new Web Server, after installing Windows 2008 R2(which is a 64bit OS and IIS7), SQL Server Standard 2008 R2 and IBM Client Access for V5R3 with its Dot Net Data Providers, I tried deploying our new project which is fully functional on an IIS6 Based Web Server, I encountered this Error

The 'IBMDA400.DataSource.1' provider is not registered on the local machine.

To remove the doubt that I still lack some Software Pre-Requesites or version conflicts  since I encountered some erros while installing my IBM Client Access, I created a Connection Tester which is Windows App that accepts a connection string as a parameter and verifies if that parameter is valid. After entering the Proper Conn String I tried hitting the button and the Test was Succesful.

So now I trimmed my suspects to My Web App and IIS7.

After Googling around I found this post by a Rakki Muthukumar(Microsoft Developer Support Engineer for ASP.NET and IIS7)
http://blogs.msdn.com/b/rakkimk/archive/2007/11/03/iis7-running-32-bit-and-64-bit-asp-net-versions-at-the-same-time-on-different-worker-processes.aspx

So I tried scouting on IIS7's management console and found this little tweak under the Application Pool where my App is a member of.

After changing this parameter to TRUE Yahoo (although I'm a Google kind of person) the Web App Works .......