Can no longer access Admin Console

I have just done the following upgrages
FreePBX to 2.10
Asterisk 1.62 - 1.8
PHP5.1 to PHP5.3

After doing the PHP upgrade, I could browse to the following:
FreePBX ip
Voicemail & Recordings (ARI)
Flash Operator Panel (FOP)

However when I try and access the Admin console, ie “FreePBX Administration” I get “The website encountered an error while retrieving It may be down for maintenance or configured incorrectly.
Error code: 500”

What might have gone wrong and how can I fix it?

I also get the following PHP errors when running amportal stop
or amportal start

"PHP Fatal error: require_once(): Failed opening required ‘DB.php’ (include_path=’.:/usr/share/pear:/usr/share/php’) in /var/www/html/admin/libraries/db_connect.php on line 14

PHP Fatal error: Call to undefined function posix_getpwuid() in /var/lib/asterisk/bin/gen_amp_conf.php on line 3
astrundir in ‘/etc/asterisk’ is set to but the directory
does not exists. Attempting to create it with: 'mkdir -p ’

mkdir: missing operand
Try `mkdir --help’ for more information.
Attempt to execute 'mkdir -p ’ failed with an exit code of 1
You must create this directory and the try again.

That said, I still seem to be able to dial out.

Seems to be a pear issue but yum install php-pear-db does not work with PHP5.3

Ensure you have the php-pear-DB package and the php-process package.