Deployed Application ASP.NET: file and web access.

[Siu]

Hi,
I've developped a Web application for my customer: this web application
allows users to modify some xml file.

The customer has deployed the web application into his domain on a IIS 5.5
or superior: his domain/network is very complex and unfortunately I don't
have a design. The problem that he encountered, occures only for some type of
user; here is the problem's explenation:

Users which belongs to the group "System Operator" and try to access the web
application, obtain the authentication window (not right!): when they have
authanticated, they can access the web application but they get an "access
denied" error when the web application access a xml file.

All other users, such as "Global System Admin" can do everything with my
application.

Please, help me finding a solution.
Thanks

 

[Siu]

I've forgotten to write that the authentication is integrated in Windows and
that there isn't any impersonation; here it is my web.config for
authentication:

<authentication mode="Windows"/>

<authorization>
<allow users="*"/> <!-- Allow all users -->
<deny users="?"/>
</authorization>

Besides, users (System Operator) who has probem by accessing xml file
through my web application, they don't have any problem by accessing xml file
directly: they can open them and also modify them, because they have NTFS
(File System) permission.

Please help me