افتح ملف register.php وابحث عن
    // check for unique email address 
    if (!empty($_POST['email']) AND $vboptions['requireuniqueemail'] AND $checkuser = $DB_site->query_first("SELECT username,email FROM " . TABLE_PREFIX . "user WHERE email='" . addslashes($_POST['email']) . "'")) 
    { 
        eval('$errors[50] = "' . fetch_phrase('emailtaken', PHRASETYPEID_ERROR) . '";'); 
    }  
أسفل منه مباشرة ضع التالي
//--- by Creative Suite -------------------- 
$creative  = strstr($_POST['email'],'@'); 
if($creative=="@hotmail.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@yahoo.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@gmail.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@usa.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@excite.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@flashmail.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@mail.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@maktoob.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@naseej.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@arabiamail.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@naseej.com.sa"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@ayna.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@kaznova.com"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@alazraq.net"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@alazraq.net"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@wearab.net"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
elseif($creative=="@arabchat.org"){ 
eval(print_standard_error('error_mailbycreative'))  ; 
}//--- by Creative Suite -------------------- 
//مع العلم انه بإمكانك اضافة أي بريد آخر 
//--- by Creative Suite --------------------  
احفظ الملف ، وارفعه 
الآن نذهب للعبارات ونضيف عبارة جديدة على البيانات التالية
Phrase Type : Front-End Redirect Messages
Varname : mailbycreative
Text : عذرا ً ، لايمكنك التسجيل ببريد مجاني ، يرجى المحاولة مرة أخرى والتسجيل ببريد خاص
المصدر
http://www.swalif.net/softs/swalif59/softs85976/