@M.Jakob That error is because you've tried to update multiple times, and it broke in the middle of the update. I'd suggest you restore your previous db backup and try again to update from the latest LS5 version from our download page.

I downloaded whole database from limesurvey before updating and i'm able to import this sql to my database to restore everything. Doesn't fix the errror though!

I have a similar problem, I also updated limesurvey from 3.* to 5.*, there didn't appear to be any issues, however now users are reporting similar error messages when filling out surveys.

500: Interner ServerfehlerCDbCommand konnte das SQL-Statement nicht ausführen: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'question.language' in 'where clause'

However, despite the error, the answers are stored correctly. 

Any idea how to tackle this? 

Hi I can confirm the same problem as TinTim.
Last Friday I've updated from 3.27.18 build 210921 (or the latest 3.x) to the than latest 5.1.10+210913. I've done this through the comfort update proces.
When I submit answers to a survey in preview mode I do not get any errors but when submitting a live survey I get the following error: Although the response is saved as a complete response.

Maybe unrelated but an update to 5.1.11 (released today) gave a database upgrade error from 473 to 475 concerning the label table (lime_labels) which was not existing in the database. Error pointed to /update/updatedb_helper.php near line 4948

Any suggestions to fix this or run some additional tests to find the cause?

As comfortupdate user I filed a ticket and the support found the solution to my problem. The error message was caused by an outdated plugin "PDFReport". Since I don't need the plugin, I disabled it which solved the problem. If you need the plugin, you need to update it, or contact the plugin's developer.