Well I'd put $id in quotes...
mems_id = '$id'
But if you give the error message or whatever...
Try adding in this to get one...
if ($delete) {
echo "Delete Worked!";
}
else {
echo("<P>Error: " .
mysql_error() . "</P>");
}
The new window may be logged out because its on a different section of the site, setting a cookie in say mysite.com/, won't work in mysite.com/otherarea/ unless you set the cookie to be read all over the site...
setcookie ('name', "value", '', '/');
with the 3rd '' just being for a time variable. Other than that I'm not sure.