Hi,
Sorry if this is unrelated, but as seeing this is a post about the beta, here goes.
I've installed the Beta 4 and have recently updated to 4 Beta 20 from an earlier version. It opened up fine the first few times, but now it gives me the following message:

Application Error
Unable to launch the ...

Hi,
I've had Sweet Home 3D for a few years, and since the introduction of lights, I've been pretty happy. When I came across a light that did not produce light, I just added a light source near it. It gives the same effect.