PHP表单/发布错误

好吧，我的发布脚本有点问题。一切都很好，除了当我键入一个像撇号一样的短语时，例如"这是我的标题"不会发布，放"这是我们的标题"会发布。不知道为什么。也许我真的不知道这些标签，我该怎么办？当它不起作用时，我会收到底部错误消息

} else {
if(isset($_POST['what'])&&isset($_POST['when'])&&isset($_POST['where'])&&isset($_POST['details'])&&isset($_POST['sponsored_by'])&&isset($_POST['collegeId'])){
$what = nl2br(htmlspecialchars(strip_tags(stripslashes(trim($_POST['what'])))));
$where = nl2br(htmlspecialchars(strip_tags(stripslashes(trim($_POST['where'])))));
$when = nl2br(htmlspecialchars(strip_tags(stripslashes(trim($_POST['when'])))));
$sponsored_by = nl2br(htmlspecialchars(strip_tags(stripslashes(trim($_POST['sponsored_by'])))));
$details = nl2br(htmlspecialchars(strip_tags(stripslashes(trim($_POST['details'])))));
    $collegeId = intval($_POST["collegeId"]);
    if(isset($_SESSION['username'])){
$username = htmlspecialchars(strip_tags(stripslashes(trim(($_SESSION['username'])))));
        $query = "select id, Name from users where username='$username' and activated = 1";
        $doQuery = mysql_query($query);
        if(mysql_num_rows($doQuery)>0){
            $results = mysql_fetch_array($doQuery);
            $userName = $results['Name'];
            $email = $username;
            $id = $results['id'];
            $query = "insert into events values(NULL,$id,$collegeId,'$what','$when','$where','$details','$sponsored_by',NOW())";
            if(mysql_query($query)) header("Location: collegeInfo.php?college=$collegeId&message=added");
            else echo "Failed to create new Event!".$query;