You have listed this question under the sketchup pro category but your user info says you are using sketchup free for the web. Assuming you are using the web version your options are limited. What formats does Archicad export in? Can you put the file into .dwg? You could download the Sketchup Pro “classic” trial (30 day working time) and use it to import a .dwg file then re-save it as .skp which could then be opened on the free web version. Or find a friend with PRO to convert it for you.