Security :: Access Denied For Logged User (anonymous User Is Fine)

I deployed a website where a logged user or an anonymous user can select data and download a XML file. The website generate the XML file in the server and then deliver it.

It works fine in my development environment, but after deployment, the anonymous user can download the file, but the logged user receive this error:

System.UnauthorizedAccessException: Access to the path 'd:HostsLocalUserheringerwebsiteUpload20110107094051.xml' is denied.

It is weird that as anonymous i can do it.

The website server help states this:

"Grant write, modify, delete access rights on website's folder

Your website executes under unique user account that by default has full control over the website's folder.
So your application can create, open, read, write and delete files and folders inside of your root folder.

There is no need and no way to change this permissions.

If, when running ASP.Net application, you still unable to create file or update it, you have to check your Web.Config file for "<Identity impersonate..." tag and remove it.

The only exception is when the application tries to modify a file or folder in "Application_Start" event of Global.asax file. This is by design that user authenticated only after the Application_Start even. Before the user is authenticated your website runs under an identity of Application Pool which is "Network services". That account doesn't have access to the folder of your website.

To make it work you eather have to move the code that tries to modify files or folders out of the "Application_Start" event of the Global.asax file or inside the event you'll need to impersonate your user by code."

But i am not using impersonate and the tag is not in my web.config.