Backup and restore

Can anyone please offer any help with this? This is affecting our forum mailouts and nightly backups.

Here's an example of the error (reposted from http://tracker.moodle.org/browse/MDL-12009):

"Fatal error: Possible integer overflow in memory allocation (8 * 8 +0) in /var/www/moodle/lib/datalib.php on line 779"

I've added a memory_get_usage() before all the common points in the file where is breaks. It usually spits out a value in and around 48 MB. Never higher than that though, even though we have allocated 512 MB to both cli and web php scripts. (Correction: I've seen it get to 140 MB before dying now.)

Our cronjob is set to run every 15 mins, in order to lighten the load of what it has to process.

For backups, it'll check and every 30 mins it will start to attempt to backup the courses again. It will eventually hit one (never the same course), and then spit out pages and pages of blank lines, followed by pages of periods (one per line), then a <br/> tag, more periods, and then the "Fatal error". Course size does not seem to matter, nor content. Our settings are set to backup up everything.

For forum posts, it will die at about the same memory usage (48 MB). I have seen it successful process posts of up to 3800 students before dying.

Also, many of the lines where it crashes are 'preg_replace' or similar. Usually something to do with an array of objects.

Here's some more details of our setup:

Moodle 1.6.3 (2006050530)

Mysql server version: 5.0.22-Debian_0ubuntu6.06.2

OS: Debian_0ubuntu6.06.2

PHP version: 5.1.2

First line of mod/forum/lib.php

<?php // $Id: lib.php,v 1.437.2.10 2006/10/10 05:15:10 vyshane Exp $

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First line of backup/backuplib.php:

<?php //$Id: backuplib.php,v 1.107.2.5 2006/08/21 20:38:44 skodak Exp $

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First line of lib/datalib.php:

<?php // $Id: datalib.php,v 1.298.2.11 2006/10/08 19:44:34 skodak Exp $

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