HP Mopier 320 digital sender module

In the organisation I work for, we have a HP Mopier 320. The problem
with this is it can't scan to email when the 'digital sender module'
software is installed on a Windows 2000 Server.
If I install the software on a Windows XP machine, it downloads the
firmware, reboots the printer and the scanner, and then I can send
pdf's to email.

Does anyone know why it works under XP Professional, but not under
Windows 2000 Server?