If I had to hazard a guess, I'd say that the SketchUp imported onto a different layer than the active layer, and that your Layer Options are set to Gray / Snap Others since that is the default. Either try to locate the design layer containing the SketchUp model, or go to View - Layer Options - Show / Snap Others. I almost always use Show/Snap Others rather than Show/Snap/Modify Others so that I can work on one thing at a time without accidentally selecting something in the background (selecting a piece of theater architecture while trying to select a lighting a fixture for example), but also know plenty of folks that have the opinion that, if an object is visible, you should be able to select it. Gray / Snap Others can be really great in helping to focus in on one layer at a time since it will gray out everything not on the active layer.
Jesse Cogswell's post in SKETCH UP TO VW, Can't see the wall, materials was marked as the answer