Usage of DirectedGraphPlugin causes errror

I installed the DirectedGraphPlugin with no errors but when I tried to use it to render a simple graph I got the following error page after pressing save:

Foswiki detected an internal error - please check your Foswiki logs and webserver logs for more information.

exec of identify %INFILE|F% failed: No such file or directory

The foswiki error log contained this:

2012-09-19T10:34:22Z warning | exec of identify %INFILE&vbar;F% failed: No such file or directory at /srv/www/foswiki/lib/Foswiki/Sandbox.pm line 547.

and the apache error log contained this:

[Wed Sep 19 10:25:56 2012] [notice] Apache/2.2.22 (Ubuntu) configured -- resuming normal operations
exec of identify %INFILE|F% failed: No such file or directory at /srv/www/foswiki/lib/Foswiki/Sandbox.pm line 547.

When I removed the graph code from the page and saved again there was no error.

Does anyone understand what is going on here and what I can do about it?

-- MilesDaffin - 19 Sep 2012

Have you installed the dependencies, and verified the paths to executables in your LocalSite.cfg ( bin/configure ) configuration? The identify command is provided by the imagemagick dependency. It's marked as optional, but your configuration might require it. Verify that the identify command is available on the default path used by the web server, or make sure $Foswiki::cfg{Plugins}{DirectedGraphPlugin}{magickPath} = ''; is set to point to the location of the imagemagick tools.

-- GeorgeClark - 20 Sep 2012