Visual Studio 2008 Issues...

[Fritz]

Please help! I am busy developing an N-Tier application for a client of mine.
This project is big and thus I would love to use Client Application Services
for security.

I have never implimented CAS before and thus I followed Microsoft's
walkthrough of CAS. Everything works fine until I run the app. I get an error
that the Machine actively refused the connection with my IP address and
specified port.

I am running Windows Vista Ultimate and Visual Studio 2008 with SQL 2005
Express Edition. When I disable my network card everything works! I thought
it might be IPv 6 but I have disabled it for testing and I still get the same
problem.

I have done the exact same steps on one of my co-workers machine and
everything works fine? The only difference is he is running Windows XP - You
can just imagine where they are putting the blame - VISTA!! but I do not
agree.

Please help me!