Can’t open .SNP attachment in Outlook 2003

I receive notifications as attachments in .SNP format. I can see the attachment in the e-mail, and when I try to open it I get a MS Outlook error message.

“Can’t create file: Notification Form.snp. 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.”

I used to be able to open these attachments with no problem.