Win 7 64bit workstations can connect using IP but not NetBios name on Win 2008 64bit server and Win 2003 32bit server

Hi,

I recently upgrade 30 users to Win7 64bit and now we are having problem connecting to either Win2008 64bit and Win2003 32bit servers using NetBios name but works using IP. 

Win7 64bit workstations TCP/IP Settings:Preferred DNS server point to DNS DC server ip address. DNS suffix for this connection point to domain name(xxxxx.com). WINS addresses point to DC IP Address.  Enable NetBIOS over TCP/IP is selected.

Any suggestions?

Thank you.