Twitter feed for website

Experts,

Over the last month or so, i have been having problems with twitter feeds on a few websites.

Can anyone explain exactly what limits are imposed on a website by twitter, before it stops allowing a feed? I have the exact same files located in two different locations, and the feed only works in one for the time being.

http://www.suremedia.co.uk/craftbeer/    (works)
http://www.craftbeerrising.co.uk/    (doesnt work)

The php code i am using is:

<?
    $username = "craftbeerriseuk";	// your twitter username here!
    $limit = 2;
    //$feed = 'http://twitter.com/statuses/user_timeline.rss?screen_name='.$username.'&count='.$limit;
    // UPDATE 10-17-2012: change in the Twitter API
    $feed = 'https://api.twitter.com/1/statuses/user_timeline.rss?screen_name='.$username.'&count='.$limit;
    $tweets = file_get_contents($feed);
    
		$tweets = str_replace("&", "&", $tweets);	
		$tweets = str_replace("<", "<", $tweets);
		$tweets = str_replace(">", ">", $tweets);
		$tweet = explode("<item>", $tweets);
    $tcount = count($tweet) - 1;

for ($i = 1; $i <= $tcount; $i++) {
    $endtweet = explode("</item>", $tweet[$i]);
    $title = explode("<title>", $endtweet[0]);
    $content = explode("</title>", $title[1]);
		$content[0] = str_replace("&#8211;", "&mdash;", $content[0]);
		$content[0] = str_replace("&amp;amp;", "&", $content[0]);
	
		$content[0] = preg_replace("/(http:\/\/|(www\.))(([^\s<]{4,68})[^\s<]*)/", '<a href="http://$2$3" target="_blank">$1$2$4</a>', $content[0]);
		$content[0] = str_replace("$username: ", "", $content[0]);
		$content[0] = preg_replace("/@(\w+)/", "<a href=\"http://www.twitter.com/\\1\" target=\"_blank\">@\\1</a>", $content[0]);
		$content[0] = preg_replace("/#(\w+)/", "<a href=\"http://search.twitter.com/search?q=\\1\" target=\"_blank\">#\\1</a>", $content[0]);
    $mytweets[] = $content[0];
}

while (list(, $v) = each($mytweets)) {
	$tweetout .= "<div>$v</div>\n";
}
?>
<?=$tweetout;?>

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I notice there has beenan update to the twitter API which is obviously causing the problems, but the behaviour since has been very frustrating...

Can anyone suggest a solid method to bring a feed into a site (using a simple block of php code) that works every time? or will we always be at the mercy of fair use limits when testing>?

Regards
Easynow