While I don't know why the installer isn't running, you can delete the save data from your SD card (through a computer; navigate via the Nintendo 3DS folder). Just be careful, and back up any files you delete.
For me, the installer ran fine with save data, but the hax itself didn't load when I had a save file in the first slot.
And when you say "humblehax installer it instantly freezes", what exactly do you mean? Do you get a yellow screen? A black screen?
I already tried to locate the savegame folder, but without success... Can you tell me how to find it?
Here http://www.3dsdb.com it sais "Citizens of Earth v1.1" (EUR version) has the Title-ID 0004000000136E00. How can that help me to find the correct folder?
I already googled for help to find the folder. And checking all files via pc (Windows 10) didn't show me any files that were edited at the date I saved for the last time in the game...
And it freezes absolutely instantly ^^'
When I "click" the installer (or press A) the background of the homebrew launcher stops moving and nothing else happens...