Mysql error bij UPDATE

<?php
if ($_GET['action'] == "update"){
                       $news_id = $_POST['news_id'];
                       $news_main = $_POST['news_main'];
                       $news_header = $_POST['news_header'];
                       $news_datetime = $_POST['news_datetime'];

                       $news_main = nl2br($news_main);
                       $news_main = eregi_replace("\n", "", $news_main);
                       $news_sql_update = "UPDATE news SET news_header = $news_header, news_main = $news_main, news_datetime = $news_datetime WHERE news_id = $news_id";
                       $bool = mysql_query($news_sql_update);
                       if($bool==1){ echo "<script language=javascript>window.alert('Bericht is bewerkt1')</script>";
                       }
                       else { echo "<script language=javascript>window.alert('Er is een fout opgetreden bij het bewerken van het bericht.')</script>";
                       $errmsg = mysql_error();
                       }
}
                       if($_GET['action'] == "delete"){
                       $news_id = $_REQUEST['id'];
                       $news_del = "DELETE FROM news WHERE news_id=$news_id";
                       $bool = mysql_query($news_del);
                                                    if ($bool==1){ echo "<SCRIPT LANGUAGE=javascript>window.alert('Bericht is succesvol gewist')</SCRIPT>";
                                                    }
                                                    elseif($bool<>1){ 
                                                    echo "<SCRIPT LANGUAGE=javascript>window.alert('Er is een fout opgetreden bij het wissen.')</SCRIPT><br>";
                                                    $errmsg = mysql_error();
                                                    }
}
?>

<?php
if ($_GET['action'] == "update"){
                       $news_id = $_POST['news_id'];
                       $news_main = $_POST['news_main'];
                       $news_header = $_POST['news_header'];
                       $news_datetime = $_POST['news_datetime'];
 
                       $news_main = nl2br($news_main);
                       $news_main = eregi_replace("\n", "", $news_main);
                       $news_sql_update = "UPDATE news SET news_header = $news_header, news_main = $news_main, news_datetime = $news_datetime WHERE news_id = $news_id";
                       $bool = mysql_query($news_sql_update);
                       if($bool==1){ echo "<script language=javascript>window.alert('Bericht is bewerkt1')</script>";
                       }
                       else { echo "<script language=javascript>window.alert('Er is een fout opgetreden bij het bewerken van het bericht.')</script>";
                       $errmsg = mysql_error();
                       }
}
                       if($_GET['action'] == "delete"){
                       $news_id = $_REQUEST['id'];
                       $news_del = "DELETE FROM news WHERE news_id=$news_id";
                       $bool = mysql_query($news_del);
                                                    if ($bool==1){ echo "<SCRIPT LANGUAGE=javascript>window.alert('Bericht is succesvol gewist')</SCRIPT>";
                                                    }
                                                    elseif($bool<>1){ 
                                                    echo "<SCRIPT LANGUAGE=javascript>window.alert('Er is een fout opgetreden bij het wissen.')</SCRIPT><br>";
                                                    $errmsg = mysql_error();
                                                    }
}
?>