Here's the offending code:
[php]
$cpp += (($_POST['tfUnit'][$i] * $cVal) * ($_POST['tfAmt'][$i] * 
100)/100); 
[/php]

$cVal is either 0 or a value returned from a function.

Since everything resolves to a number here, theoretically, what's up with 
this errror?

To clarify:

Well, perhaps I'm going about this incorrectly, but ideally I'd like to 
roll-up a total for $cpp; the If - else is there because the function 
compares a value passed to determine if the value is present in a lookup 
array, if so, then it does some calculations and returns either 0 or the 
result of the calculations.
[code]
$cpp = 0;
for($i = 0; $i < $_SESSION['numIng']; ++$i)
  {
       $portion = explode(":" , $_POST['selMeasure'][$i]);       
       $cVal = getConversionValue($_POST['tfUnit'][$i], $portion[0], 
$portion[1]);
       if($cVal !=0)
           {
                $cpp += ($_POST['tfUnit'][$i] * $cVal) * ($_POST['tfAmt']
[$i] * 100)/100; 
           }
       else
            {
                $cpp += ($_POST['tfUnit'][$i] * $portion[1]) * ($_POST
['tfAmt'][$i] * 100)/100;
            }
}
[/code]

My first suggestion would be to break apart all the operations to see which
one is giving you the error.


$cpp = 0;
for($i = 0; $i < $_SESSION['numIng']; ++$i)
{
  $portion = explode(":" , $_POST['selMeasure'][$i]);
  $cVal = getConversionValue($_POST['tfUnit'][$i],
                             $portion[0],
                             $portion[1]);

  $cVal = ($cVal != 0)? $cVal : $portion[1];

  $temp1 = $_POST['tfUnit'][$i] * $cVal;
  $temp2 = $_POST['tfAmt'[$i] * 100;
  $temp3 = $temp1 * $temp2;
  $temp4 = $temp3 / 100;

  $cpp += $temp4;
}


nik

Problem solved.

Forgot $cVal is an array, 

so it should be $cVal[0]...DOH!!!