Hi,

 I am developping a visitors tracking script for a website but on a test server not on a real website.

 I have to test my script, to see if it log correctly traffic if it react correctly when several visitors are in at the same time and so ... But how ?

Do you know if it exist a kind of program thant send traffic to you website to simulate visitor ?

 It's really important, thank a lot if someone can help me. 

Yes, there's plenty.

I use microsoft's own version though, which you can get from here:

http://www.microsoft.com/downloads/details.aspx?familyid=e2c0585a-062a-439e-a67d-75a89aa36495&displaylang=en

Thank a lot, I will try this one tonight !

 I tried to install that software in Vista, but it requires a DLL no longer included in (this version of) Windows.

 "MSVCP50.dll"

Too bad, I'd like to give it a try.

Edit: I got it to work, but had to run the program as administrator.  Thanks for the tip!

Just grab a copy of that MSVCP50.dll from wherever you can (it's available via a quick google). and stick it in the same folder as the web tool .exe