Security certificates

From: Bobbie (bobbie_at_yhti.net)
Date: 08/30/03 

Date: Sat, 30 Aug 2003 10:46:09 -0700

At my workplace, we now use security certificate when we
send emails. I could always access my work email from
home until now. When I try to open a message with a
security certificate from home, I can't. Instead of the
message, I get a little square with smime.p7m next to it.
How do I open these files? Thanx