Cannot run Windows Server 2008 R2 with VirtualPC

I've installed Windows7 64bit (Enterprise) on my AMD Athlon 64 System.
After all automatical Updates, I've installed the VirtualPC 6.1.7600.
(64bit)

I created a new Virtual machine:
Windows Server 2008, an own VHD, 1 GB RAM...

When I try to install "Windows Server 2008 R2 (64bit)", the setup
interrupts with this errormessage:
"Attemping to load a 64-bit application, however this CPU is not
compatible with 64-bit mode"

Is it not possible to run a 64bit-OS with VirtualPC on Windows7?

 

No. Virtual PC can only run 16 or 32 bit operating systems (and even 16 bit
OS is no longer officially supported). Virtual PC itself is a 32 bit app.
The 64 bit "version" of it merely means that it includes the 64 bit drivers
for VPC to work on 64 bit host operating systems.

You should be able to install the 32 bit version of Windows Server 2008 (of
course, this can't be R2 so if you really need R2, this isn't an option).

Another option would be to use a different virtual machine technology that
does support a 64 bit guest OS (assuming any at all do; I don't know).

Mike