Aterisk and FreePBX on Ubuntu 12.04

Hi,

I am trying to install Asterisk and FreePBX on Ubuntu 12.04.4 distro based on the library document:

Deploy VoIP Services with Asterisk and FreePBX on Ubuntu 12.04 (Precise)

I'm pretty sure I've followed the instructions exactly and everything seems to install and configure correctly untill I get to:

./install_amp

I get the following output and error at this point, and no additional files are created in /var/www/html so the FreePBX Administraion page isn't there. I can get to my domain but it's just the Apache It Works! page.

SETTING FILE PERMISSIONS

Permissions OK

Done

done with apply_conf.sh

creating missing #include files..OK

OK

Setting permissions on files..OK

Checking for upgrades..No further upgrades necessary

Creating or updating freepbx_conf settings….OK

Setting freepbx settings form /etc/amportal.conf

freepbx setting [ASTMANAGERHOST] set to [localhost]

PHP Fatal error: Class 'notifications' not found in /opt/freepbx/amp_conf/htdocs/admin/libraries/utility.functions.php on line 1364

I researched this and found one other reference on Google but no explanantion or resolution for the ptoblem.

Any help would be greatly appreciated.

Thanks!