access denied on attachments Outlook 2003

This is how I re-create this problem in Outlook 2003
1) open an email with an attachment
2) double-click on the attachment to open it
3) Open or Save? Choose Open
4) Get error message - Access Denied
I can forward the email to another email address and pick it up from my
other computer and it opens up fine. I can also save the file to the hard
drive and open it. It happens with numerous types of attachments - word
files, jpg, .wmv, etc.

This is new - within the last few days.