can not be can generate the security sspi context

[sitmapa]

1 windows 2003 server,
sql 2000 server installed,

3 win xp sql client,
1 win 98 sql client,
1 win 2k prof client,

my vb6 application connect and work fine with the win98 and 2k., accessing and processing data from the sql server,

but, in the win xp client, the first time connect fine my app to the sql server, and about 10 to 15 minutes after, receive the error like:

[odbc sql server driver] can not generate the sspi security context.

thank´s for any help.....