569236 Traffic redirecting script total review

I have a website with a traffic redirecting script. In general this script redirects hits/visitors from A to B. The script is placed on a dedicated server. Munin is installed. Right now there seems to be a leak of some sort. If 10 hits are coming from A, around 6-8 are being delivered to B. I need someone to go through the script code and check if it can be more optimal or find out where the leak is. The leak could also be due to the server specs, but right now i cant say where its located. The script is not very big, its located in 1 folder with 3-4 php pages.