2D Export to DWG crashing on my mac

Hi there… I am trying to export floor plans and elevations into 2D DWG or DXF format, but sketch up hangs every time, and/or crashes my computer. It works fine on a simple model, but not the full home model I’m working on. I’m using SU 2014, latest version, on Mac OSX 10.7.5. Would appreciate any suggestions!

Thanks so much,
Deborah