George.....
You did not show us how you connected the transistors to the LED from the 8255 chip. You should use a circuit similar to this shown below for each LED. Connect to the 8255 port A instead of the 8051 as shown.

Also check your 8255 chip initialization to make sure you are making Port A be an output port.

With this circuit an output of a ZERO will make the LED turn on and a ONE will turn the LED off.



Michael Karas