PHP & MySQL INSERT INTO problem -

any ideas why following code not adding database once user fills out form? i'd appreciate it.

thank you!

    if($_session['loginsuccess']==1) {          // ============================================================         // = create table of current tasks stored in database =         // ============================================================         $userid = $_session['userid'];         $result = mysql_query("select * tasks userid = '$userid'");         echo "<div id=\"draggable\" class=\"ui-widget-content\"><table border='5'><tr class=\"ui-widget-header\"><td><u>task name:</u></td><td><u>class:</u></td><td><u>due date:</u></td><td><u>task type:</u></td></tr>";         echo $_session['userid'];         while($row = mysql_fetch_array($result)) {             $taskname = $row[1];              $class = $row[2];              $taskduedate = $row[3];              $tasktype = $row[4];               echo "<tr><td>'$taskname'</td><td>'$class'</td><td>'$taskduedate'</td><td>'$tasktype'</td></tr>";         }         echo "</table>";          function addnewtask ($name, $class, $duedate, $type) {             mysql_query("insert tasks values ('$userid','$name', '$class', '$duedate', '$type')");         }      if($_post['taskname'] != null) {             addnewtask($_post['taskname'], $_post['class'], $_post['duedate'], $_post['duedate']);         }  ?>   <!-- <img border="1" alt="new" src="/newtask.png" id="newtask" onmouseclick="showtaskfield"/> --> <p><form name="newtask" method="post" action="index.php" id="newtask"><br>     task name: <input name="taskname" type="text"> (necessary)<br>     class: <input name="class" type="text"><br>     due date: <input name="duedate" type="text" id="datepicker"><br>     type:      <input type="submit"></p></div> 

try getting rid of ' around variables in insert statement. if nothing echoing mysql_error().