I have a similar problem, I want to test the version of Construct, but I can not see anything when I click preview, the window opens, but the game does not start, is black screen.
If the debug window opens, but its just displaying a blank void of nothingness, then it probably has something to do with your code and not our trusty crusty Construct engine.
If you'd like, you can post some of the initial script and we can see whats going on.