DB Error: no such field On Event Registration
This is because of a missing field in the contribution log table. See the following question and answer for next steps:
How can I deal with a missing or corrupt binary (&quot;advanced&quot;) log table?

So if you don't care about existing logs, you should just be able to turn logging off then back on, otherwise that post gives some more advice.

For either step, I'd suggest backing up your database first just in case something gets more corrupted.