Here's your model with some notes pointing to things that 3d printing does not like. I've been playing around with shapeways recently - they accept collada files so you don't even need to go to a .stl. In general, your model needs to be scaled to fit on print bed, be water-tight, and not have any interior faces. And no over-lapping faces. Following those rules, I can consistently produce 3d-printable model directly from SketchUp (for shapeways, anyhow.) library 11.3[jf].skp