cannot alter excel attachment in powerpoint presentation

A powerpoint 2003 presentation document was e-mailed to me and I was asked to make changes to to an excel 2003 attachment within the presentation. I cannot open the excel attachment to make the changes. Other users on different pcs can make changes to this presentation with no difficulties. I have tried using the “detect and repair ” utility in Outlook, reinstalling office 2003, completely removing office 2003 and re-installing , all with no success. I am using office 2003 standard with service pack 2. An article on the web indicated that an issue like this exists where you have office 2003 and Norton anti-virus installed ,but I use McAfee anti-virus not Norton.