From Singed Labcoat:
Automator Virtual Input allows automator to simulate mouse movements, clicks and drags as well as keyboard presses. In doing so, it allows automator to access previously unavailable programs and functions and preform whatever action you want automator to preform.
This is carried out by first compiling a list of actions to be carried out within automator, then calling the Automator Virtual Input virtual machine to execute them. This gives you total control over the mouse and keyboard allowing automator to finally reach its full potential as a productivity tool.