samba - Jul 2005 - Problem using other program than explorer XPd

I have a Samba server to use with 50 windows client. Just a workgroup 
working very will with the windows explorer. But when a client tries to 
connect with another program ex: Outlook express to attach a file from 
the server, the message says "access 
denied".  I have checked the log files but nothing wrong there... 

Please help me,

Ma?l