Column suddenly drops down

I modified this one theme as I transferred FTP-Blogger site to WordPress. Everything went fine and worked. Also after many nights of editing CSS and PHP files. But then all the sudden when I went to homepage the layout started to look very bad with right side column dropped down. It is 3 column layout and 100% CSS valid with no errors.

Note that the problem only occurs in homepage, and when browsing << older or newer >> posts but not when clicking on to specific post, archive lists or categories. Look and try by your self…

Please any ideas? Heres the address:
https://www.sitruunapuu.net/blog

Few things that I already tried after searching help from here and with Google:

– I removed few widgets for a moment to check if they or their content causes column to act weird. No results.

– I looked from theme PHP files for open div tags but I didn’t find.

– Also I tried to check if there are too wide images in posts. Nope.

– Then I looked for overlappings from CSS. Nope.

Or am I blind (tired)? I tried various things and now I really need some new aspects, thanks!!