Windows 7 Windows installation encountered an unexcepted error

[gogax17]

Hello everyone..

When I try to install Windows 7 BETA, this message appears

Windows installation encountered an unexcepted error. Verify that the installation sources are accessible, and restart the installation.
Error code : 0xC0000005.

I dont know why this problem appears.. I use Windows Vista SP2.

I have Intel Centrino Duo 2.2 GHz , 2 GB Ram & nVidia GeFORCE 8400M G

What can be the problem..??

Thanks for replies