For around a week now, many Blogger users have experienced Bx-error codes when attempting to upload a new template to their blogs when previously these templates had worked just fine. I discovered the reason for this on the Blogger Help Group after reading this post from Gatsby, a Blogger Employee: Recently we changed the way our template editor accepts certain third party code, so that it is now less tolerant of certain templates. We did this because we had seen a lot of data corruption due to ‘bad templates,’ and we are trying to stave off some of these issues pre-emptively