Nigel currently has a few days off and I'll be happy to assist in English, while he is away. I hope this is OK with you.
From the screenshot, the bootstrap column classes seem to be added correctly.
Can you please make sure that Bootstrap's resources are being loaded on the website?
You can go to WP Admin -> Toolset -> Settings and from "General" tab, select "Toolset should load Bootstrap 3.0" for the "Bootstrap loading" option.
( screenshot: hidden link )
Let me know how it goes and if the issue persists, please also share the link to the page with that search form.