Is your frame trying to take secure or protected (requires a hardware event) actions?
Is it a parent or otherwise related to such a frame?
SetPoint() will cause taint-related errors (100% of addon code causes taint but not all taint is problematic) by design as it could be used to create a "smart button" otherwise (same with hide/show/scale)
In some cases all you'll need to do is wrap your frame movement / show / hide / scale code in a combat check and make sure you never try to take those actions while in combat.
In some cases that is not enough (when taint spreads to a secured Blizzard codepath and causes it to error further down the road)
You need to at least point out your specific addon and code for anyone to offer an opinion really
