Were you supposed to quote me, but quoted RoC (again) instead?
Else, is there any real point to quoting the same guy twice?
Anyhow, most people who give mon's TR moves, forget this:
You can give a mon a TR in-game, it sets a flag in that list, so that you won't have to use the same TR on it again, and can simply go to the move relearner.
As such, if you forgot to set the TR flag, and haxed in a TR move onto the mon, the mon ends up rightfully illegal.
(TR moves can only be legally given, when the flag is also given)
Without telling us what mon and what move you're trying to accomplish, there's nothing much we can do except assume you forgot to do that.
Do tell us what combination of mon and TR move you were trying to do.