3x3x3 LED Cube Software?

In my program, only one LED of the whole cube lights, the only problem is that some are only supplied with 0.2V, unlike others, which are supplied with the regular 2V. I noticed that when one LED in a column is supplied with 2V, all others in the column are also supplied with this voltage. This means that either the LEDs of a column get 0.2V or 2V.

I do not think the problem is in my software which I would likely to be develop as an iphone app, but rather the circuit.
Can it be that the transistors may not properly steer?