Citrix Access Gateway server configuration failes : "Failed To Create Sample Logon Point"

In this case the problem is caused by the network service account, which has insufficient permission to %system Root%\Microsoft.net\Framework\v2.0.50727\Temporary ASP.NET Files.

In order to solve this problem you need to provide modify rights to %system Root%\Microsoft.net\Framework\v2.0.50727\Temporary ASP.NET folder for the "localhost\network service" account.