samba - Nov 2008 - long filename

Dear all

My server running samba 3.0.28 on RHEL 5.2 using winbind to authenticate
user from window 2003 AD.
Today i got a strange problem, a user working on window xp client trying to
copy a file on samba share,
but this process ask for short name for file,denying copying long filename's
file.  Our other clients are
working perfectly, and day before today that clients also had no such issue.


thanks