Well first things first .
About unzipping please note that we never find any difficulty in unzipping the files using 7zip and winrar before in windows and there is no other user who have reported the same issue either .
It might be issue with the application that you are using to unzip .
About the duplicate topic issue .
Please check this screenshot :
http://prntscr.com/awj6x9
you created same topic previously this is why the system was showing that duplicate topic warning .
Well i have merged both the topic now .
As it seems the issue is not related to theme but with the application that you were using So can we close this now .