I am having the same problem. On Mac os X, sketchup 8. even though the plugins folder is there, when I try to install v-ray it tells me that the plugin folder does not exist. the location of my plugin folder is in root /Library/Application Support/Google SketchUp 8/Sketchup/plugins and not under the user library... Has anyone found a solution? it looks like a bug, do you know if they have fixed it yet? thanks