Arduino Mini Pro pin D8 is always HIGH

I am using Arduino Compatible Pro Mini w/ ATMEGA328P Electronic Building
http://www.dealextreme.com/p/arduino-pro-mini-w-atmega328p-electronic-building-blocks-interactive-media-improved-version-104332

When I've connected 8 LEDs to it, the LED that was connected to pin D8 was always ON.

Despite the configuration the problem is still exist:
pinMode(8, OUTPUT);
digitalWrite(8, LOW);

Please help.
Thank you.

Disconnect all of the leds, write a sketch that blinks D8 and report the results.

The other option is show your code for review.

Does it make any difference if you set it as an input?