Could be your virus software is preventing it from opening.

Some suggestions he
Error message when you try to open a publication in Publisher: "Publisher cannot
open the file" or "Publisher has detected a problem"
http://support.microsoft.com/kb/928890/en-us

How to troubleshoot a damaged publication in Publisher
http://support.microsoft.com/default...b;en-us;198256



--
Mary Sauer MVP
http://msauer.mvps.org/

"Sherri Grezel" wrote in message
...
I have a Publisher 2003 file that was emailed to me. I am running Publisher
2003 as well on my computer, but Publisher returns an error message, Unable
to open file??? Any ideas?