NetBIOS Domain Name Field Has a 15 Character Length Limitation (Q226144), http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q226144“RESOLUTION
To work around this issue, you can specify your NetBIOS domain name from left to right using a unique name (up to 15 characters) in your enterprise that matches a portion of your DNS domain name. For example, if your DNS Fully Qualified Domain Name (FQDN) is support.us.microsoft.com, and your enterprise also has a DNS FQDN of support.uk.microsoft.com, you can create a NetBIOS domain name called support.us.”