This is a really strange bug that I'm currently running into as well. The reason it's strange is because when I was using SQLObject and CherryPy before I even tried out TurboGears, I had no problems with the same rows that are now giving me trouble. And I looked at the line in dbconnection.py that's supposedly raising the error, it's the same in both the TurboGears distribution and the version I was using.
Something is apparently calling str() on a unicode field when it's being inserted. There is a way around it, it seems: make the column accept None, then update it with the unicode value later on: Table.uniField = UnicodeCol(default=None) ... Table(uniField=None, ...) ... Table.uniField = stringThatCausedProblemBefore (or) Table.set(uniField=stringThatCausedProblemBefore)
