I use MeshLab to sort out all the troubles with SketchUp exports - either DAE or OBJ format.

If Meshlab doesn't work, I process the DAE or OBJ inside Blender.

I note that Sketchup can produce non-manifold surfaces which Meshlab doesn't like.

From what I know Poser doesn't like triangles and long thin polygons.  Some re-meshing of your SketchUp export may be required, but that will throw the material mapping.

Some SketchUp models simply refuse to work nicely.  What more can I say......

Eternal Hobbyist