3 Speed Front Derailleur can't reach small gear
The chainwheel does not sit at the correct chain line is the answer.

The most common cause is that you have an axle length shorter/longer than the ideal chain line. In this case, you have a shorter axle length.

Did you add another chainring into your crankset? If the answer is yes, you will need to tweak around: either adding spacer (not recommended) or find a compatible front derailleurs (better get to the LBS for trial/error fitting).
If the answer is no, then it will be the frame that cause you the problems, albeit unlikely. I always solve this problems by finding a correct axle length for my crankset.

You can refer to this article for more information, from Lord Sheldon.
http://www.sheldonbrown.com/chainline.html