I'm using Sikuli (sikulixapi-1.1.0).
I have 2 monitors. When I use my primary monitor, everything is ok. When I also use the second monitor, it does not work.
I make a screenshot on the second monitor and I wrote this:
Screen s = new Screen(1);
Error
Possible cause in case you did not touch the mouse while script was running: Mouse actions are blocked generally or by the frontmost application. You might try to run the SikuliX stuff as admin.
You seem to be having issues with the multimoitor setup.
A similar question was asked on launchpad and can be found here: https://answers.launchpad.net/sikuli/+question/295379
The basic advice was "Make sure you are using the latest version of 1.1.1 in your java context"