Hi Alex,
As you see the screenshot, the button located left side of screen,
it is near the camera that within 100 units, and no collision objects between them.
I solved it with tricky way, but still PlayMaker 1.7.3 looks doesn't work well with Unity 4.1.5.
: first, import PlayMaker 1.5.7 and made 'Cube' Button -> worked well.
Second, Update PlayMaker via Unity Asset Store.
-> Now "MousePickEvent" action works.
Problem, 'Collision Event' is not working now.
The object with Trigger collider doesn't catch any objects, and it doesn't send any events.
I think using 1.7.3 later on my Unity version. I posted I'd like to download 1.6.1 version, and test on Unity 4.1.5 to check actions are O.K.
http://hutonggames.com/playmakerforum/index.php?topic=4905.0Kindly, Alex replied on my post. I will send e-mail with the invoice.
By the way, Where can I find your e-mail address?
Thank you! Alex.