By "first warning", Brutus meant that you got a red box telling you to reconsider when you were typing out your reply. It was situated right above the text box with the reply. Just pay attention to things in general.
As for the warning on your profile, which, as was clarified, you got for that same necromantic reply, it automatically gets reduced by 5% every day. Nothing to worry about there, just something to keep in mind. A mod that was abandoned in 2011 (and had necro-posts going up to 2012, right before your reply, which is kind of funny) is very likely to still be dead.