the only agent that can affect the setting of cookies is the agent, i.e. the browser, check your privacy settings.
I have found Firefox's options allow you the best ability to view cookies. Here's the code that I used in one place to set cookies:
setcookie('logosMain',$PHPSESSID.":".$PHPSESSID.":1:".time(),time()+(3600*24*90),'/','.logos-ministries.com');
yours is only different from mine on the last value - which means you can accept from myite.com OR www.mysite.com or even admin.mysite.com (the best way I think).