Last versions of Sketchup (2013,2014,2015) have recently change the import specification for collada and kmz ending up in that importing from Cityplanner export have crashed.
This issue is now resolved and also exporting large datasets from Cityplanner have been optimized when it comes to the memory consumption. Still exporting large datasets needs to run 64-bit browser to handle memory consumption.
Also the Sketchup function “geo-located” have been changed or suffer from a unwanted bug (Still works in Sketchup 8). Importing a kmz-file in Sketch shows that the model is not geo-located (small icon down in the left).
But there is a work-around, so just by changing the correct value back and forth geo-locates the imported file. This only works handling import of 1 file so your Cityplaner export should be done as combined.
See screen-shots below.