Windows 7 : Windows 2003 Print Server
Came across an issue today where a Windows 7 client would not print to a Windows 2003 x64 print server. The solution was a registry key to disable the use of Async. RPC for printing:
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\
Right-click Printers, point to New, and then click DWORD.
Type EnabledProtocols.
Rigkt-click EnabledProtocols.
In the Value data box, type 6.
Close Registry Editor.
Reboot the client then test printing again.
More info here: http://support.microsoft.com/kb/2269469