• You don't check the result of $dbh->prepare.
• You don't check the result of $dbh->fetchrow_array.
• Your loop can be replaced with $sth->fetchall_arrayref.
• You can also condense the code further using $dbh->selectall_arrayref.

use strict;
use warnings;

use DBI ();
use HTML::TableTiler ();

my $dbh = DBI->connect("DBI:mysql:project")
   or die "Can't connect to Oracle database: $DBI::errstr\n";

my $matrix = $dbh->selectall_arrayref("SELECT * FROM modules");
die "Unable to fetch query results: $DBI::errstr\n" if $dbh->err;

my $tt = HTML::TableTiler->new();
print $tt->tile_table($matrix);
[download]

Update: I was obviously tired! Fixed the problems identified in replies.