AVR Freaks

I can't upload a project to my new Atmega328pu, which is clocked at 8MHz. I can reach it with the AtmelStudio over a AVRISP mk2 programmer, however when I try to upload a simple "Blink" program, I get a message like this:

Unexpected signature 0x001e0114 (expected 0x001e9514).

Sometimes I get this:

Verifying Flash...Failed! address=0x0000 expected=0x0c actual=0x6e

Just to be sure, here is my code:

#include <avr/io.h>
#define F_CPU 8000000UL
#include "util/delay.h"

int main(void)
{
    DDRB = 0b11111110;
    while (1)
    {
        PORTB = 0b00000100;
        _delay_ms(1000);
        PORTB = 0b00001000;
        _delay_ms(1000);
    }
}