help : KRB_AP_ERR_MODIFIED error

[gexpatri (nospampls)]

Hello,

we currently work with a small Lan :
1 file server with Windows 2000 server
1 mail server : Windows 2000 exchange server
8 laptops running under Win XP Pro

We have recurrent problems of login with the laptops : no network 
sharing reconnections, no mail server found, but internet ok.

Rebooting several times, and reinitializing the password in the Active 
Directory seem to solve the problem sometimes.

The event log of the laptops shows this system error :

The kerberos client received a KRB_AP_ERR_MODIFIED error from the server 
COMPANY$.  This indicates that the password used to encrypt the kerberos 
service ticket is different than that on the target server. Commonly, 
this is due to identically named  machine accounts in the target realm 
(COMPANY.NET), and the client realm.   Please contact your system 
administrator.

Does anyone know how to solve this practically ; it's getting really 
annoying spending 1 hour each day to logon.