From what I understand,
you've modified your database to use utf8mb4_unicode_ci rather than a latin based utf8_general_ci or latin1_swedish_ci collation; which from what I'm seeing is causing you a huge amount of errors because UBB.threads doesn't know how to work with the data you are presenting to it (please, stop making new posts for every new MySQL error as they all stem from the same issue and can be amended to the same thread).
UBB.threads is a software product from the mid-90's that's been ported up through standards through the years, and is long older than the UTF8 became the web standard; hence why it does not fully support 4-byte utf8 unicode such as what current digital Chinese or Japanese characters use, at this point.
We understand that English isn't your first language, and you don't fully understand it; but some of your bug reports are so vague and hard to follow that we're unsure of what the ultimate problem is, let alone how to reproduce the errors that you're getting.
