cpan[7]> install GraphViz
Running install for module 'GraphViz'
Checksum for /home/uce/.cpan/sources/authors/id/R/RS/RSAVAGE/GraphViz-2.20.tgz ok
Configuring R/RS/RSAVAGE/GraphViz-2.20.tgz with Build.PL
Can't exec "dot": Ficheiro ou directoria inexistente at Build.PL line 14.
Please install Graphviz from http://www.graphviz.org/.
No 'Build' created  RSAVAGE/GraphViz-2.20.tgz
  /usr/local/bin/perl Build.PL --installdirs site -- NOT OK
Failed during this command:
 RSAVAGE/GraphViz-2.20.tgz                    : writemakefile NO -- No 'Build' created