Second time: you did it again, did you forget the right way?
Third time: we've talked about this before, what's the deal? If this keeps happening, we're going to have to reconsider your employment here as a web developer
Fourth time: last warning
Fifth time: bye
Good people don't do this sort of thing repeatedly. If your organization refuses to get rid of people like that, you shouldn't stay at that place either.
I see that you gave the person 5 warnings - I feel 3 times is less and this is exactly what I would do. Its so much better to give people more chances rather than less and then letting them go instead of letting an ego or something similar come in detween earlier.
Please do not take number 5 so literally. It's the process that matters. You do 2, 3, 4, 5, 6, 7, 8, 9 or 10 chances whatever suits your needs. The actual point is you don't fire people on the first mistake unless you're an asshole.
Second time: you did it again, did you forget the right way?
Third time: we've talked about this before, what's the deal? If this keeps happening, we're going to have to reconsider your employment here as a web developer
Fourth time: last warning
Fifth time: bye
Good people don't do this sort of thing repeatedly. If your organization refuses to get rid of people like that, you shouldn't stay at that place either.