Open chat prompt, type "/target ", shift click a name from the chatwindow and press return. This will cause taint issues with the TargetUnit() function. I think hooksecurefunc needs to be used if possible.
I'm experiencing this as well. However I have Prat installed and the error comes up as it being Prat that is causing the error. Disabling Prat will then say CensusPlus is causing the error. Disabling C+ and enabling Prat will still say Prat is causing the error.
Whats interesting is if I type /target drazen... I get the error. If I type /target draz... I don't and it targets me.
I guess I could be falsely accusing CP for the taint problem, but when I disabled CP, the taint issue was resolved. CP may interact with another addon to produce this taint issue.