Can't call method "new" on an undefined value

Bonjour,

Je viens de r=E9cuperer la maintenance d'un site tournant sous PERL, que
je suis en train de d=E9couvrir, et j'ai le message suivant : Can't call
method "new" on an undefined value at
C:/WebSites/www.bvdep.com/cgi-bin/dbModules/Search.pm line 44.
La ligne 44 est la suivante : $body->add($topClass->new);

Je souhaiterais savoir :
1) ce qu'indique ce genre de message en g=E9n=E9ral?
2) dans le cas pr=E9sent, o=F9 dois-je chercher l'erreur?

D'avance, un grand merci pour votre aide.

Voici le code en question:

sub print
{
my $self =3D shift;

my $head =3D Head->new;
$head->link(Link->new(Consts::DOCSPATH()."styles.css"));
$head->title(Title->new("BvDEP - Customer Support - Search results:
"=2E$self->{FIELDS}->{SEARCHSTRING}));
$head->script(Script->new("javascript",
Product->new->navRolloverScript().$self->_script.DropDown->new->script));
my $body =3D Body->new;

my $topClass =3D $topClass{lc substr $self->{FIELDS}->{AREA}, 0, 1};
# $body->add(NeutralPageTop->new("press"));
$body->add($topClass->new);
# $body->add(NeutralPageTop->new(1));

my $table =3D Table->new;
$table->add(VSpacerRow->new(8));

my $navTable =3D Table->new;
my $areaConstants =3D AreaConstants->new($self->{FIELDS}->{AREA});

if ($areaConstants->area eq 's')
{
$navTable->add(RowOfCells->new(Products->new('c',
1)->supportDropdown));
$navTable->add(VSpacerRow->new(7));
$navTable->add(RowOfCells->new(ELearningQuickLinks->new));
$navTable->add(VSpacerRow->new(7));
$navTable->add(RowOfCells->new(NewsItems->new("p", undef, "c")));
}
else
{
$navTable->add(RowOfCells->new(Categories->new($areaConstants->area)));
$navTable->add(VSpacerRow->new(7));
$navTable->add(RowOfCells->new(Products->new($areaConstants->area)->dropd=
own));
$navTable->add(VSpacerRow->new(7));
$navTable->add(RowOfCells->new(NewsItems->new("p", undef,
$areaConstants->area)));
}

my $mainTable =3D $self->_mainTable;

my $contentTable =3D Table->new;
# $contentTable->add(RowOfCells->new(Spacer->new(56), $mainTable));
$contentTable->add(RowOfCells->new(Spacer->new(18), $navTable,
Spacer->new(17), $mainTable));
$table->add(RowOfCells->new($contentTable));

$table->add(VSpacerRow->new(1));

$table->add(RowOfCells->new(Null->new->add(Spacer->new(8),
Copyright->new(19))));

$body->add($table, Hidden->new(WHATTODO=3D>'FREETRIALFORMRESPONSE'));

my $height =3D 255;
$body->onmousedown("closeDropDowns()");
$body->onload("formResponseSpan.style.height=3Ddocument.body.clientHeight-=
$height");
$body->onresize("formResponseSpan.style.height=3Ddocument.body.clientHeigh=
t-$height");

Page->new($head, $body)->print;
}