owc11 on windows 2003 web edition - Access denied

[Amine]

Hi all,
Could somebody please enlighten me with the following issue:
I have an apllication that uses OWC11 to generate a chart.
Everything works fine until i try to use ExportPicture.
I get an Access denied exception which I tried to resolve by making sure
that the authentication was set to windows integrated, UNCHECKED allow
anonymous access, and finally used <identity impersonate= "true" />.
Unfortunately this did not resolve the issue.
Please help!!
Many Thanks