magento cron schedule不工作，没有心跳

Question

I have inherited a magento site and the cron schedule does not work. It was set in magento with */5**** and the same in cpanel. I installed AOE Scheduler and all the emails that had been stuck in the queue came through but now I just get a message "Last heartbeat is older than XX". If I run the scheduled tasks manually the emails come through but I get a "405 Error - Not Allowed" page and I find all my file permissions have been changed to 666 (the number of the beast). I have been setting my file permissions to d - 755 and f - 644 but depending on which forum you read this could be wrong. Please help, I have been on this for days.

This is my cron.php

<?php

// Change current directory to the directory of current script
chdir(dirname(__FILE__));

require 'app/Mage.php';

if (!Mage::isInstalled()) {
    echo "Application is not installed yet, please complete install wizard first.";
    exit;
}

// Only for urls
// Don't remove this
$_SERVER['SCRIPT_NAME'] = str_replace(basename(__FILE__), 'index.php', $_SERVER['SCRIPT_NAME']);
$_SERVER['SCRIPT_FILENAME'] = str_replace(basename(__FILE__), 'index.php', $_SERVER['SCRIPT_FILENAME']);

Mage::app('admin')->setUseSessionInUrl(false);

umask(0);

$disabledFuncs = explode(',', ini_get('disable_functions'));
$isShellDisabled = is_array($disabledFuncs) ? in_array('shell_exec', $disabledFuncs) : true;
$isShellDisabled = (stripos(PHP_OS, 'win') === false) ? $isShellDisabled : true;

try {
    if (stripos(PHP_OS, 'win') === false) {
        $options = getopt('m::');
        if (isset($options['m'])) {
            if ($options['m'] == 'always') {
                $cronMode = 'always';
            } elseif ($options['m'] == 'default') {
                $cronMode = 'default';
            } else {
                Mage::throwException('Unrecognized cron mode was defined');
            }
        } else if (!$isShellDisabled) {
            $fileName = basename(__FILE__);
            $baseDir = dirname(__FILE__);
            shell_exec("/bin/sh $baseDir/cron.sh $fileName -mdefault 1 > /dev/null 2>&1 &");
            shell_exec("/bin/sh $baseDir/cron.sh $fileName -malways 1 > /dev/null 2>&1 &");
            exit;
        }
    }

    Mage::getConfig()->init()->loadEventObservers('crontab');
    Mage::app()->addEventArea('crontab');
    if ($isShellDisabled) {
        Mage::dispatchEvent('always');
        Mage::dispatchEvent('default');
    } else {
        Mage::dispatchEvent($cronMode);
    }
} catch (Exception $e) {
    Mage::printException($e);
    exit(1);
}

This is my cron.sh

#!/bin/sh
# location of the php binary
if [ ! "$1" = "" ] ; then
    CRONSCRIPT=$1
else
    CRONSCRIPT=cron.php
fi

MODE=""
if [ ! "$2" = "" ] ; then
    MODE=" $2"
fi

PHP_BIN=`which php`

# absolute path to magento installation
INSTALLDIR=`echo $0 | sed 's/cron\.sh//g'`

#   prepend the intallation path if not given an absolute path
if [ "$INSTALLDIR" != "" -a "`expr index $CRONSCRIPT /`" != "1" ];then
    if ! ps auxwww | grep "$INSTALLDIR$CRONSCRIPT$MODE" | grep -v grep 1>/dev/null 2>/dev/null ; then
        $PHP_BIN $INSTALLDIR$CRONSCRIPT$MODE &
    fi
else
    if  ! ps auxwww | grep "$CRONSCRIPT$MODE" | grep -v grep | grep -v cron.sh 1>/dev/null 2>/dev/null ; then
        $PHP_BIN $CRONSCRIPT$MODE &
    fi
fi