Undefined offset in a webcrawler on PHP

<code>Hey guys, im trying to write a content specific webcrawler in PHP, and I keep getting an undefined offset on line 68. Im really not sure where I went wrong, so any help would be great!

1    <?php
2   
3    include("C:\Program Files\PHPCrawl_082\libs\PHPCrawler.class.php"); 
4    
5    set_time_limit(0);    
6    
7    $domain = "http://www.carrollcountyohio.us/";
8    
9    
10    $content = "Election Results";
11    
12    
13    $content_tag = "Election Results";
14    
15    
16    $output_file = "ElectionsURL.txt";
17    
18    
19    $max_urls_to_check = 10;
20    
21    $rounds = 0;
22    
23    $domain_stack = array();
24    
25    
26    $max_size_domain_stack = 1000;
27    
28    
29    $checked_domains = array();
30     
31    
32    while ($domain != "" && $rounds < $max_urls_to_check) {
33        $doc = new DOMDocument();
34     
35        @$doc->loadHTMLFile($domain);
36        $found = false;
37     
38    
39        foreach($doc->getElementsByTagName($content_tag) as $tag) {
40            if (strpos($tag->nodeValue, $content)) {
41                $found = true;
42                break;
43            }
44        }
45     
46        $checked_domains[$domain] = $found;
47    
48        foreach($doc->getElementsByTagName('Election') as $link) {
49            $href = $link->getAttribute('href');
50            if (strpos($href, 'http://www.carrollcountyohio.us/') !== false && strpos($href,      $domain) === false) {
52                $href_array = array_pad(explode("/", $href, 2), 2, $href);
53                if (count($domain_stack) < $max_size_domain_stack &&
54                    $checked_domains["http://www.carrollcountyohio.us/".$href_array[2]] === null) {
56                    array_push($domain_stack, "http://www.carrollcountyohio.us/".$href_array[2]);
58                }
59            };
60        }
61    	
62    	if(isset($domain_stack[0])) {
63    	}
64    		
65    		
66    	
67     $domain_stack = array_unique($domain_stack);
68        $domain = $domain_stack[0];
69        unset($domain_stack[0]);
70        $domain_stack = array_values($domain_stack);
70        $rounds++;
72      
73    
74    }
75     
76    $found_domains = $domain_stack;
77    foreach ($checked_domains as $key => $value) {
78        if ($key == 2) {
79            $found_domains .= $key."\n";
80        }
81    }
82     
83    file_put_contents($output_file, $found_domains);
84    ?></code>