Backup module uses 100% CPU

We are running Centos 5.8, PHP 5.2.5, Asterisk 1.8.15.1 and Freepbx 2.10
The backup & restore module is 2.10.0.41

Whenever we run a backup, manual or automatic - the CPU hits 100% with PHP

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
24812 asterisk 25 0 32320 19m 5848 R 100.0 1.0 5:54.50 php
1 root 15 0 2168 668 576 S 0.0 0.0 0:00.46 init
2 root RT -5 0 0 0 S 0.0 0.0 0:00.21 migration/0
3 root 34 19 0 0 0 S 0.0 0.0 0:00.04 ksoftirqd/0
4 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root RT -5 0 0 0 S 0.0 0.0 0:00.09 migration/1
6 root 39 19 0 0 0 S 0.0 0.0 0:00.01 ksoftirqd/1
7 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/1
8 root 10 -5 0 0 0 S 0.0 0.0 0:00.01 events/0

This is caused by the backup module processes:
sh -c /var/lib/asterisk/bin/backup.php --id=1 2>&1
php /var/lib/asterisk/bin/backup.php --id=1

whenever we stop those processes the CPU returns to normal and PHP stops using 100% CPU

Any ideas why the backup module is causing PHP to max out the CPU ??