I am trying to read a link from one page, print the url, go to that page, and read the link on the next page in the same location, print the url, go to that page (and so on...) All I'm doing is reading the url and passing it as an argument to the get_links() method until there are no more links. This is my code but it throws a Fatal error: Call to a member function find() on a non-object. Anyone know what's wrong?

<?php

        $mainPage = 'https://www.bu.edu/link/bin/uiscgi_studentlink.pl/1346752597?ModuleName=univschr.pl&SearchOptionDesc=Class+Subject&SearchOptionCd=C&KeySem=20133&ViewSem=Fall+2012&Subject=&MtgDay=&MtgTime=';

        get_links($mainPage);

            function get_links($url)
            {
                $data = new simple_html_dom();  
                $data = file_get_html($url);

            $nodes = $data->find("input[type=hidden]");
            $fURL=$data->find("/html/body/form");
            $firstPart = $fURL[0]->action . '<br>';

            foreach ($nodes as $node) {
            $val = $node->value;
            $name = $node->name;
            $name . '<br />';
            $val . "<br />";

            $str1 = $str1. "&" . $name . "=" . $val;
            } 
            $fixStr1 = str_replace('&College', '?College', $str1);
            $fixStr2 = str_replace('Fall 2012', 'Fall+2012', $fixStr1);
            $fixStr3 = str_replace('Class Subject', 'Class+Subject', $fixStr2);

            $fixStr4 = $firstPart . $fixStr3;
            echo $nextPageURL = chop($fixStr4);
            get_links($nextPageURL);
        }
    ?>