my application not working in IE

hi,
i have integrated my application with drupal
in user.module, after the user is authenticated i am setting a cookie with the users id as its value.
this cookie i am accessing in my application for getting the users details.
this works fine in FF, but in IE apparently its failing the if(isset($_COOKIE['id'])) part n going to the else part
i tried clearing all cookies and changing IE settings to allow all cookies but still its not working
can anyone tell me why this is happening and how i can overcome this

thanking in advance