mutale

I am writing a Tacking software that should track converstion with sevral sites. when a User click a banner it goes to a PHP file located on my server and place a cookie at the client. At the other site I placed an IMG tag at the convertion page that leads to (at the src) to another PHP file that read the cookie write something to my DB and then erase the cookie. Now it doesnt work, for some reson I cant read the cookie. Please help me find a way to do it, I cant place anyting but a IMG tag on the other sites that I need to count the convertions at.

I need to integrate a tracking system with a few clients, the clients agree to place <img src="....."> tags but not to place a file on there servers. I need to set a cookie on the visitor computer and when the visitor preform an action to read the cookie and send the cookie infotmation to my server. I tried everything, and I cant read the cookie, I can set the cookie using a javascript file that I placed on my server. But to read the cookie and send the information I need to use PHP or ASP file, and I cant do that unless the visitor has 3rd party cookies enable. How can I intergrate the systems?