Exception Access denied , creating a new excel object in ASP.Net

From: Hemant shastri (Hemantshastri_at_discussions.microsoft.com)
Date: 07/28/05 

Date: Wed, 27 Jul 2005 21:48:03 -0700

In my web application i am reading the data from excel file and inserting the
records into the database.(In ASP.net C#)
 
for some users i am getting exception "Access denied" at the following line
of the code.
Excel.Application=new Excel.Application();
for some user it is working fine.
In IIS -->properties-->directory security-->Authentication mode is
"Integrated Authentication" , needed to find the login id of the user.
Web.config file identity impersonate option is also true.
How can i avoid this error message?
Please help...Thanks to all of you for investing the time and replying.