One of my friends has used the free 8h SketchupPro version as a way to import his .dwg files which he then saves and re-opens with the SketchupMake version to work on them. I was hoping to do the same but my pro version (I still have at least 7h30 left on it) won't recognise the dwg file even saved as an earlier version or as a early DXF version.
I've checked and it won't recognize as import-able any of my dwg files.

Hi, I drew up a plan on autocad which I would like to import into Sketchup Pro but SU won't recognize my .dwg file. The name is grayed out when I attempt to open it.
I can't seem to find anyone with this problem online (I'm not receiving any "error" messages I just simply can't click on the desired file.) Any suggestions?
I've got Autocad 2013 (19.0.55.108) and the free 8h version of Sketchup Pro (8.0)
I'm working on a macbook pro, my operating system is 10.6.8.