Dimmer not turning bulb on or off
One red wire on your dimmer should be connected to the supply from
the wall live
The other red should be connected to the load the one that switches
the lamp on off
Black should be connected to your neutral
The Green should be connected to your bare conductors or earth (ground)


As mentioned previously you should have as physically minimal copper exposed as possible realistically none it should all be inside the connector the insulation should go right to the connector itself. 

Test to find what you need?


Your earth or ground when tested to neutral should present 0v
When tested from your neutral to your live supply full voltage should be present
When tested from your neutral to your load the wire that goes to the lamp 0v should be present as this is only live once in your particular case has gone through the dimmer


Could you provide if possible a picture showing the model number and one of the front or alternatively if it is simply an open up dimmer case a picture showing the electronics on the inside.
Usually you will have one red power in, one black power return path or neutral, one ground or earth and finally one power out to your load (lamp light)