Can't locate GD.pm in @INC

Bonjour à tous,
j'ai un problème qui me bloque mon travail :

voila le contenu de errors_log de apache.

Can't locate GD.pm in @INC (@INC contains: /usr/lib/perl5/5.8.0/i386-linux-threa
d-multi /usr/lib/perl5/5.8.0 /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-mu
lti /usr/lib/perl5/site_perl/5.8.0 /usr/lib/perl5/site_perl /usr/lib/perl5/vendo
r_perl/5.8.0/i386-linux-thread-multi /usr/lib/perl5/vendor_perl/5.8.0 /usr/lib/p
erl5/vendor_perl /usr/lib/perl5/5.8.0/i386-linux-thread-multi /usr/lib/perl5/5.8
.0 .) at ./include/trafficMap/trafficMap.pl line 9.
BEGIN failed--compilation aborted at ./include/trafficMap/trafficMap.pl line 9.
Can't locate GD.pm in @INC (@INC contains: /usr/lib/perl5/5.8.0/i386-linux-threa
d-multi /usr/lib/perl5/5.8.0 /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-mu
lti /usr/lib/perl5/site_perl/5.8.0 /usr/lib/perl5/site_perl /usr/lib/perl5/vendo
r_perl/5.8.0/i386-linux-thread-multi /usr/lib/perl5/vendor_perl/5.8.0 /usr/lib/p
erl5/vendor_perl /usr/lib/perl5/5.8.0/i386-linux-thread-multi /usr/lib/perl5/5.8
.0 .) at ./include/trafficMap/trafficMap.pl line 9.
BEGIN failed--compilation aborted at ./include/trafficMap/trafficMap.pl line 9.

comment résoudre ce problème .
merci d'avance pour vos réponses