Why Can't I Program my Atmega168 Pro Mini?
Your hookup seems to be correct. However check if there is a capacitor on the pro-mini board between DTR and reset pin, some arduino clones don't come with one.
If there isn't any you can simply connect a capacitor like this:
Reset pin (Arduino Uno) -&gt; Capacitor (0.01uF for example) -&gt; DTR (pro mini). The reason for this hookup is exmplined well here