Error while virtualizating Vista64 on Vista64.

I'm trying to virtualize my Vista64 (on my Vista64 host, an Intel Core 2 Duo), but I've got the following error:
Can you help me?

Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:
1. Insert your Windows installation disc and restart your computer.
2. Choose your language settings, anche then click "Next."
3. Click "Repair your computer."
If you do not have this disc, contact your system administrator or computer manufacturer for assistance.
File: \windows\system32\boot\winload.exe
Status: 0x000035a
Info: Attempting to load a 64-bit application, however this CPU is not compatible with 64-bit mode.
Can you help me?
