phpvirtualbox tutorial - problem

[mcc28x]

Hi,

I have followed the tutorial http://www.howtoforge.com/managing-a...x-ubuntu-12.04 but have an error when I try to login at myserver/phpvirtualbox/

I use the default username/password (admin/admin) but ge tthe following error message:

Exception Object
(
    [message:protected] => Error logging in to vboxwebsrv.
    [string:Exception:private] => 
    [code:protected] => 64
    [file:protected] => /var/www/phpvirtualbox/lib/vboxconnector.php
    [line:protected] => 188
    [trace:Exception:private] => Array
        (
            [0] => Array
                (
                    [file] => /var/www/phpvirtualbox/lib/auth/Builtin.php
                    [line] => 45
                    [function] => connect
                    [class] => vboxconnector
                    [type] => ->
                    [args] => Array
                        (
                        )

                )

            [1] => Array
                (
                    [file] => /var/www/phpvirtualbox/lib/ajax.php
                    [line] => 119
                    [function] => login
                    [class] => phpvbAuthBuiltin
                    [type] => ->
                    [args] => Array
                        (
                            [0] => admin
                            [1] => admin
                        )

                )

        )

    [previous:Exception:private] => 
)

The only information in the logfile is:

VirtualBox web service 4.1.18 r78361 linux.amd64 (Jun 20 2012 14:50:49) release log
00:00:00.000 main     Log opened 2012-08-17T12:52:51.706645000Z
00:00:00.000 main     OS Product: Linux
00:00:00.000 main     OS Release: 3.2.0-29-generic
00:00:00.000 main     OS Version: #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012
00:00:00.000 main     OS Service Pack: #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012
00:00:00.000 main     Executable: /usr/lib/virtualbox/vboxwebsrv
00:00:00.000 main     Process ID: 3993
00:00:00.000 main     Package type: LINUX_64BITS_UBUNTU_12_04
/var/log/vboxweb.log (END)

There are some threads on the web about this error but none of them particularly conclusive. Anyone help me resolve this please?

regards

Mark