Import and parse XML with PHP
===

I am trying to import a XML file via API into my php script which then will parse said XML file and extract a string. Ive searched across the webspace for an answer, and though I have found a ton of resources I still cannot get this script to work. 

The XML file that I am loading will look something like this

   

    <api version="2">
      <currentTime>2012-07-28</currentTime>
        <result>
          <rowset name="accounts" key="accountID" columns="accountID,accountKey,balance">
            <row accountID="555555555" accountKey="6666" balance="7777777777.23"/>
          </rowset>
        </result>
      <cachedUntil>2012-07-28</cachedUntil>
    </api>

I am trying to get my php script to fetch the value of the attribute <b>balance</b>.
This is the code that I have put together so far:

    <?php
    
    $apiurl = "api.some-arbitrary-api-site.com;
    $xml = simplexml_load_file($apiurl);
    
    print_r($xml);
    $balance = $xml->balance;
    print_r($balance);    

    ?>

This returns:

    SimpleXMLElement Object ( ) 


Also following some other web tutorials I have tried this change

    $balance = $xml->row->attributes()->balance;
    print_r($balance);
Which spits out

    Warning: main() [function.main]: Node no longer exists in C:\xampp\htdocs\EVE\progress\import.php on line 22
    
    Warning: main() [function.main]: Node no longer exists in C:\xampp\htdocs\EVE\progress\import.php on line 22

What am I doing wrong? The end result is for the page to load this API and fetch the balance once every two days and store the data to be used in a chart rendered using highchart.

Any help will be appreciated!
Thanks