There's a syntax error in the code. I had to modify either the client or server file to get it working again... I think it was the server file.
Replace the existing server.cs file in the Script_Flooding folder with this one.
You do this by going into your Add-Ons folder, finding a .zip file named Script_Flooding and open it with WinZip. Then, click the link provided by Snaily, save it to your desktop, and click, hold it down and drag it into the WinZip window. It will replace the old broken server.cs with the good one that Snaily posted. If it asks you to overwrite, say Yes.