RSS Junk message ?

[TimberFloorAu]

When trying to access some of our rss feeds, we get this:

XML Parsing Error: junk after document element
Location: http://www.mysite.com/forum/external.php?type=rss2&forumids=8
Line Number 1, Column 7:<br /><strong>Warning</strong>: Invalid argument supplied for foreach() in <strong>[path]/includes/class_postbit_alt.php(474) : eval()'d code</strong> on line <strong>22</strong><br /><br /><strong>Warning</strong>: Invalid argument supplied for foreach() in <strong>[path]/includes/class_postbit_alt.php(474) : eval()'d code</strong> on line <strong>22</strong><br /><br /><strong>Warning</strong>: Invalid argument supplied for foreach() in <strong>[path]/includes/class_postbit_alt.php(474) : eval()'d code</strong> on line <strong>22</strong><br /><br /><strong>Warning</strong>: Invalid argument supplied for foreach() in <strong>[path]/includes/class_postbit_alt.php(474) : eval()'d code</strong> on line <strong>22</strong><br /><?xml version="1.0" encoding="ISO-8859-1"?>
------^

Any suggestions please