Single Phase Energy Meter using Atmega32
You are doing two things wrong as far as I can see.

Firstly, a 230VAC mains supply is a sinewave at 50 or 60Hz and has a positive peak amplitude of \$\sqrt2\$ x 230V = 325.3 volts and a negative peak amplitude of the same. This means the full peak to peak input voltage into your device is 6.5 volts peak to peak (assuming an attenuation of 100 which I think you are aiming for). I think this goes well beyond the ADC input range and may well damage your device.

The second problem is that your attenuator will have a common mode voltage of half AC voltage i.e. 115V AC. Usually, because the neutral wire is grounded, this means the AC voltage will try and lift your circuit to this voltage and (hopefully) if you have your design grounded, it will fail but in doing so you will have shorted out half the attenuation resistors meaning your attenuation is now only 50:1.

These are the main issues as I see them. Because you may not have been aware of these problems it is STRONGLY advised that you choose a safer method of extracting the AC voltage i.e. use a step down ISOLATING transformer.

AC MAINS IS QUITE OFTEN LETHAL.