I can't open an excel attachment, any idea why and/or how to fix this?

I've been able to open all excel attachments except for this one in particular that I get. The error message I get says Microsoft cannot access this file becuase file name or path does not exist, file is being used by another or workbook you are trying to save has the same name.... It's definately not the last 2.

Oh ya, and I'm able to open the attachment in Outlook just fine.

Thanks