why my 2nd dropdown not popolated?

///////// Getting the data from Mysql table for first list box//////////
$quer2=mysql_query("SELECT DISTINCT reg_name,reg_id FROM region order by reg_name");
///////////// End of query for first list box////////////

/////// for second drop down list we will check if category is selected else we will display all the subcategory/////
$cat=$_GET['cat']; // This line is added to take care if your global variable is off
if(isset($cat) and strlen($cat) > 0){
$quer=mysql_query("SELECT DISTINCT candm_name,candm_id FROM candm where reg_id=$cat order by candm_name");
}else{$quer=mysql_query("SELECT DISTINCT candm_name,candm_id FROM candm order by candm_name"); }
////////// end of query for second subcategory drop down list box ///////////////////////////


/////// for Third drop down list we will check if sub category is selected else we will display all the subcategory3/////
$cat3=$_GET['cat3']; // This line is added to take care if your global variable is off
if(isset($cat3) and strlen($cat3) > 0){
$quer3=mysql_query("SELECT DISTINCT brgy_name FROM brgy where candm_id=$cat3 order by brgy_name");
}else{$quer3=mysql_query("SELECT DISTINCT brgy_name, brgy_id FROM brgy order by brgy_name"); }
////////// end of query for third subcategory drop down list box ///////////////////////////


my 2nd dropdown box without data and my third dropdown always have a data..please help..thanks