Cannot logon with SP4

[isabelle_michard at mail.schneider.fr]

     Hello everybody
     
     We have installed samba v1.9.18p4 on solaris 2.5.1. And it works 
     perfectly on PC NT4 workstation SP3.
     
     Now we have just received new PC NT4 with SP4. and now we are no more 
     able to loggon to the server (but we do see the server name in the 
     explorer).
     
     The NT message when clicking onto the server name is :
     \\<server> is not accessible.
     The account is not authorized to login from this station.
     
     
     It seems that the account MUST BE the same name as the station name 
     (but we want to login AS users).
     
     What do you think ? PLEASE HELP ME...
     Thank you for helping us !
     
     Isabelle MICHARD //\/\
     SCHNEIDER ELECTRIC
     France