I have found a mistake on someone's code published online: what is the protocol? I have been using an econometrics toolbox for around 2 years and it is great, very useful. It is available from someone's personal website.

I have found a mistake in one piece of code which has set me back for a considerable amount of time. It is a small change but with vast consequences. Instead of questioning the code, I did my idea. 

Now that I have found the problem, what is the protocol for highlighting this? Is emailing the author necessary?
Now that I have found the problem what is the protocol for highlighting this, is emailing the author necessary?


It isn't necessary, but it is the right thing to do, if you don't, you're responsible for causing others set backs that will waste them a considerable amount of time.