session - cookie issues

Hi all, I am having issues with users not being able to post their details to my site. The system uses sessions, so when they hit the index page a test cookie is set thus: setcookie('djst', 'test'); and then I test whether that cookie is set on the next page. If not, I direct the users to an informational page. This works my end in FF and IE6 (sec settings tested at low, medium and medium high) but appox 1 in 20 users cannot get past the cookie warning, even if they set their security settings to low in IE. I am also setting PHPSESSID to something of my own, as I hear that IE does not like PHPSESSID (correct?). Any ideas? -- http://www.web-buddha.co.uk