Try placing a redirect when it finish sending the email i had this problem the hole day discovered that theUE might have a bug if that is not filled.
I see you have
//Send Mail All Entries
if (""!="") {
header("Location: ");
}
wich means you did not set a file to redirect after sending the email.
check this post i just made a few min ago
showthread.php?t=2911
even if you not using addt just add the file to redirect there like a thank you page or something and it will work :)