krb5 error code 52 - can't login

[l9phan1@upstream.xomcorp.com]

I am using a Windows 2000 as a KDC for my Kerberos environment.  I have many
Kerberos Unix clients running SUN Solais 2.6 and 8.  When a user is in more
than 32 groups on the Windows 2000 server then that user can't login into
the Unix box.  

I got the following error message when using kinit command:
kinit (v5): krb5 error code 52 while getting initial credentials.

When use telnet or rlogin I just get a "login incorrect" message.

Do you have any idea how to fix this problem.  Thank You.