The extra $db was the problem. It works now.
mysql_select_db('realest1_proppost');
$query2 = "UPDATE customerindex SET cfirstname='$cfirstname', clastname='$clastname', cmidinitial='$cmidinitial', cstaddress='$cstaddress', cunitnum='$cunitnum', ccity='$ccity', czip='$czip', cphone='$cphone'...