Hello Murray
The Gramps page (http://portableapps.com/apps/education/gramps_portable) on the PortableApps web site suggests that it was packaged by someone called 'Bart S.'. I suggest contacting this person through PortableApps and asking for the pygoocanvas and graphviz dependencies to be included in their package. Given the specialised nature of PortableApps, installing the dependencies separately on a USB stick will probably not be sufficient. The Windows AIO Gramps packages are not intended to run purely from a USB stick either.
The Gramps project writes the Gramps software, which other projects are free to take (respecting the GPL license) and package it for their own target operating systems. We do provide a small range of packages (http://sourceforge.net/projects/gramps/files/Stable/) but this does not include the PortableApps package. The Gramps project has not been involved in packaging the PortableApps version of Gramps as far as I am aware.

From: Murray Strome <wmstrome@yahoo.com>
To: gramps-users@lists.sourceforge.net
Cc: gary.burton@zen.co.uk; bury_lancs@yahoo.co.uk
Sent: Wednesday, 15 February 2012, 5:27
Subject: Re: [Gramps-users] Gramps Portable -- graphview.py not loaded
On Tuesday, February 14, 2012 1:45 PM "Gary Burton" <bury_lancs@yahoo.co.uk> wrote:
You do need to install pygoocanvas as Marco suggests but the error message refers to Graphviz which is a different piece of software. Graphviz is used by graphview but also lots of other features in Gramps. I suggest contacting the person who packaged the portable apps version of Gramps and asking for Graphviz and pygoocanvas to be included too.
Alternatively use the all-in-one (AIO) version of Gramps which I understand already includes all of these dependencies.

Thanks for this information. However, I would appreciate someone telling me HOW to download and install pygoocanvas and GraphViz, or to download and install the all-in-one (AIO) version of Gramps on my PortableApps.com USB memory stick.

I thought that it was you who packaged the the portable app version. If not, who should I contact?

Thanks for any help.