Permission issue with DTS and ASP

Please, help me. I am calling a DTS Package from an ASP page using stored procedure and xp_cmdshell.
DTS package transfers data from SQL tables to excel files to network shared directory. I am getting a access denied error when the DTS package fails. I used the UNC path for the Excel files within DTS package.
I can run the DTS Package from Enterprise Manager successfully, but cannot run it from the ASP page.

Thanks for any and all help.