I too have SU8 with SP3.2 on Windows 7, but don't have the exact problem you describe even with older models from Sketchup warehouse. What I do get, is that when I download a warehouse model it bugsplats the first time I try to run it, but if I double click on the model file with Sketchup closed, so that the file opens and starts a new instance of Sketchup at the same time, it runs 'perfectly', despite the warning messages that the file is an older version and may not work. Sorry I can not be more help, but I cannot replicate what you describe.
Just curious, does this happen if you start with a empty file and create a very simple model such as a single SketchyPhysics cube falling under gravity?