issues with simplexml_load_string/SimpleXMLElement on PHP 5.1/Linux

This works fine under WAMP with PHP 5.3 and Windows XP on my dev machine. But on a Unix/PHP 5.1 env it doesn't. I am looking to pull out "LineNumber" and "TaxAmount" from the XML for each iteration of the loop below, for each iteration "$tax_line" is always an object of simplexml_load_string ( http://us2.php.net/manual/en/functio...oad-string.php ).

$tax_line is the following object, which obviously has a type of "object".

Does anyone know how I would do this?

The point where things seem to get screwy between Windows and Linux is when I come to this line: $tax_lines = $tax_document->TaxLines->TaxLine;

The SimpleXMLElement is a print_r dump of "$tax_line".

Any help would be really appreciated. Have been looking at this for ages now!

Cheers,
Picco

SimpleXMLElement Object
(
    [@attributes] => Array
        (
            [Id] => 1
        )
 
    [LineNumber] => 1
    [TaxSummary] => SimpleXMLElement Object
        (
            [EffectTaxRate] => 0.09752
            [TaxAmount] => 24.38
            [TaxBasis] => 250.00
        )
)
$response_xml = simplexml_load_string($data);    
$document_status = $tax_document->DocumentStatus->Success; // this can be outputted fine
$tax_lines = $tax_document->TaxLines->TaxLine;                
 
foreach ($tax_lines as $tax_line) {
 
  $linenumber = (string) $tax_line[0]->LineNumber;            
  $taxamount = (string) $tax_line[0]->TaxSummary->TaxAmount;
 
}