Outlook 2002-Attachment error

When opening a file attachment (excel file) in Outlook 2002, I receive the following message. Can’t create the file; xxx.xls. Right-click the folder you want to create the file in, and then click Properties on the shortcut menu to check your permissions for the folder. However, I have been able to open this file previous to today. I have checked the security tab to be sure I have Full Control of the entire c: drive, plus I am an administrator on this machine.