multiple forms working together?

[LingoOutsider]

<!-- standard html jump menu -->
<script type="text/JavaScript">
<!--
function MM_jumpMenu(targ,selObj,restore){ //v3.0
  eval(targ+".location='"+selObj.options[selObj.selectedIndex].value+"'");
  if (restore) selObj.selectedIndex=0;
}
//-->
</script>

// get all values from URL (form set to get)

if(isset($_GET['planttype'])){$planttypeget = $_GET['planttype'];}
if(isset($_GET['plantname'])){$plantnameget = $_GET['plantname'];}
if(isset($_GET['description'])){$plantdescriptionget = $_GET['description'];}
if(isset($_GET['costnumber'])){$costnumber = $_GET['costnumber'];}
if(isset($_GET['planttype'])){$rownumbers = count($_GET['planttype'])+2;}else{$rownumbers = 2;} 

!standard conect to database & query!

<form method="get">
<table width="100&#37;" border="1" cellspacing="1" cellpadding="1">
        <tr>
          <td width="75" align="center">Item</td>
          <td width="75" align="center">No.</td>
          <td align="center">Description</td>
          <td width="75" align="center">Total</td>
          <td width="75" align="center"></td>
		  <!--calculating amount of rows to place in -->
        </tr><?php $rowcounter=0; while($rownumbers > $rowcounter){if($rowcounter > 0&&$deleterow['X']!=$rowcounter){?>
        <tr>
          <td align="center">&nbsp;</td>
          <td align="center"><input type="text" name="itemcodes[<?php echo $rowcounter; ?>]" class="boxsquare" value="<?php echo $itemcodes[$rowcounter]; ?>"/></td>
          <td><?php $planttype=$_GET['planttype']; if(!$planttype[$rowcounter]){ ?>
		  <!-- selecting plant type tree/shrub/misc -->
		  <select name="selectType" class="box" onchange="MM_jumpMenu('parent',this,0)">
            <option value="">Type</option>
			<?php 
			while($plant_type = mysql_fetch_array($find_type)){ ?>
            <option value="?<?PHP echo $URL_1.$URL_2.$URL_3.$URL_4."&planttype[".$rowcounter."]=".$plant_type['treeShrub']; ?>"><?php echo $plant_type['treeShrub']; ?></option>
			<?php $typeno++;} ?>
          </select><?php } ?>
		  
		  <?php $plantname=$_GET['plantname'];if($planttype[$rowcounter]&&!$plantname[$rowcounter]){ ?>
		  <!-- ########## select plant name apple/pear/turnip ######### -->
		  <select name="selectPlant" class="box" onchange="MM_jumpMenu('parent',this,0)">
            <option value="">Name</option>
			<?php 
			$find_plant = mysql_query("SELECT * FROM $user[WorkS] WHERE treeShrub='$planttype[$rowcounter]' GROUP BY plant ");
			while($plant_name = mysql_fetch_array($find_plant)){ ?>
            <option value="?<?PHP echo $URL_1.$URL_2.$URL_3.$URL_4."&plantname[".$rowcounter."]=".$plant_name['plant']; ?>"><?php echo $plant_name['plant']; ?></option>
			<?php } ?>
          </select><?php } $plantdescription=$_GET['description'];if(!$plantdescription[$rowcounter]){echo $plantname[$rowcounter]." - ";}  ?>
		  
		  <?php if($plantname[$rowcounter]&&!$plantdescription[$rowcounter]){ ?>
		  <!-- ########## select work description plant/remove/reduce ########## -->
		  <select name="selectDescription" class="box" onchange="MM_jumpMenu('parent',this,0)">
            <option value="">Description</option>
			<?php 
		  $find_description = mysql_query("SELECT * FROM $user[WorkS] WHERE plant='$plantname[$rowcounter]' GROUP BY type");              // plant description listing
			while($plant_description = mysql_fetch_array($find_description)){ ?>
            <option value="?<?PHP echo $URL_1.$URL_2.$URL_3.$URL_4."&description[".$rowcounter."]=".$plant_description['type']; ?>"><?php echo $plant_description['type']; ?></option>
			<?php } ?>
          </select>
		  <?php } $descriptionmod=$_GET['newdescription']; if($plantdescription[$rowcounter]){?>
		  <!-- ########## display selection results ########## -->
		  <textarea name="newdescription[<?php echo $rowcounter; ?>]" cols="60" rows="3"  ><?php 
		  if($descriptionmod[$rowcounter]!="") echo "$descriptionmod[$rowcounter]"; 
		  else echo "$plantname[$rowcounter] - $plantdescription[$rowcounter]"; 
		  ?></textarea>
<br/>
		  
		  
		  <input type="submit" name="adddescription[<?php echo $rowcounter; ?>]" class="boxsmall" value="add description"/>
		  <input type="submit" name="updatedescription[<?php echo $rowcounter; ?>]" class="boxsmall" value="update description" /><?php } ?>
		  
		  
		  
		  
		  </td>
          <td align="center">
		  <!-- ########## place a number to calculate total cost ########## -->
		  <input type="text" name="costnumber[<?php echo $rowcounter; ?>]" class="boxsquare" value="<?php echo $costnumber[$rowcounter]; ?>"/></td>
          <td align="center">
		  <!-- ########## remove a row button ########## -->
		  <input type="submit" name="itemnumber[<?php echo $rowcounter; ?>]" value="X" class="boxsquare"  /></td>
        </tr><?php }$rowcounter++;} ?>
        <tr>
          <td align="center">&nbsp;</td>
          <td align="center">&nbsp;</td>
          <td align="center">&nbsp;</td>
          <td align="center"><!-- total placed here ?!--></td>
          <td align="center">&nbsp;</td>
        </tr>
      </table>
<form>

I have lots of PHP and would like to implement your awsome code for numbers in the total column (where costnumber[] is) but no matter how I try to change or adapt it, it won't work!?

Please help

Thanks

+if you know how I can submit my form when using a jump menu so values entered into the fields total / No. are passed on and recorded!?