Please run the Window > Libfredo Settings > Fredo6 Plugins Information for Sketchucation Support menu command in SketchUp and copy/paste the output into your reply.
@Dave-R Got it! Thanks Dave...it did seem like overkill to lock both the viewport and the layers, but it seemed like one of my viewports was shifting (even though camera positions weren't changed) and I thought maybe I had been double-clicking into the viewport(s) w/o realizing it. Still not sure what I did, but it seems to be working now.