Hi everyone, this is my first post here. Sorry if there is a lot here, better safe than uninformed.
I use the current versions of php, and Mysql make my pages dynamic. I use Dreamweaver MX 6.1 to build my pages

I have been looking for a number of days on updating my database with multiple checkboxes through an array. The user selects a row with the checkbox to designate which record is updated. No matter what I do, either my loop does not work correctly, or I get no result at all with these notice errors.

"Notice: Undefined index: txtstudent0 in E:\www\intranet\new\admin_today.php on line 11

Notice: Undefined index: chkstudentdel0 in E:\www\intranet\new\admin_today.php on line 11"

I am using radio boxes to "choose" a php script to execute. Currently, I have a delete script that works fine, and an update that does not.
Here's my form code:

<form action="admin_today.php" method="post" name="formstudent" id="formstudent">
          <table width="100%" border="0">
            <tr align="center" valign="middle"> 
              <td colspan="3" bgcolor="#FFFFCC">This is the information already 
                stored into the database</td>
            <?php do { ?>
            <tr bgcolor="#FFFFCC"> 
              <td align="center" valign="middle"> 
                <input name="chkstudentdel[]" type="checkbox" id="chkstudentdel[]" value="<?php echo $row_rsstudentaffairs['TodayID']; ?>"> 
              <td colspan="2" align="center" valign="middle"> 
                <textarea name="txtstudent[]" cols="60" rows="3" id="txtstudent[]"><?php echo $row_rsstudentaffairs['TodayInfo']; ?></textarea>
            <?php } while ($row_rsstudentaffairs = mysql_fetch_assoc($rsstudentaffairs)); ?>
            <tr align="center" valign="middle" bgcolor="#FFFFCC"> 
              <td>Select your function</td>
              <td width="44%"><input type="radio" name="goal1" value="1">
                Delete Record 
                <input name="goal2" type="radio" value="2">
                Update Record</td>
              <td width="21%"><input type="submit" name="Submit" value="Submit"></td>
Here's my Delete and Update Code So far
if (isset($_POST['goal1'])) //select the radio button delete, then submit
      $ids_to_delete = join(',' , $_POST['chkstudentdel']); //sql for deleting follows
       mysql_query("DELETE FROM tblbcmttoday WHERE TodayID IN ($ids_to_delete)");
elseif (isset($_POST['goal2'])) //select the radio button update, then submit
		for ($i = 0; $i < count($_POST['chkstudentdel']); $i++) // loop that doesn't work
	  	mysql_query("UPDATE tblbcmttoday Set TodayInfo = '".$_POST['txtstudent'.$i]."' Where TodayID IN ".$_POST['chkstudentdel'.$i]."");
Right now I'm getting no changes in my database, can anyone help? I'm not terribly new, or super code guru - I'm right in the middle of everything making sense.

Thanks so much