Sims 3 Create a World - cannot export

I have made a world in CAW, and since Edit in Game does not work anymore, I wanted to export it and just use "Edit town" in the sims to build on the lots. 

Problem is, every time I try to export and enter a Thumbnail the whole thing crashes.

is there a way to fix this, or an intirely other way to export? 

thank you :)