Too short reply messages (help!)

Hello everybody,

sometimes I am posting some folders on the site that I am hiding the message because otherwise the users don't have respect for the sharing, so I'm using this code

but now my problem is, sometimes users reply toooooo short messages like "tnx", or "thanks", or "goog", etc. etc.

and that makes me unhappy

I've heard of my friend that you can install to the forum something so the users are required to reply a message that must be at least 20 characters for example... Is it possible to install something for the forum
because otherwise this makes me very unhappy

If you let me know something back I will be promise... Thank you godfather

PEACE

I would suggest posting this in the suggestions forum, with a poll for members to vote. I have looked for a java code but cant find one that i can get working for me.

U Can Post At The Suggestions Forum And Remember To Add A Poll