Application Launch Failure in Web Interface 5.0 through 5.3
Applications fail to launch on a windows 2008 server when .NET 1.1.x or .NET 4.0 is installed on the Web Interface server. When the user clicks to launch the published application, nothing happens. The browser might briefly show a request, however, the Citrix ICA client never attempts to connect.
Read more about the workaround -> http://support.citrix.com/article/CTX123921