Check if both Lens and Cloud have a packagedeclaration. Blow are my working code snippets:

Main program:

#!/usr/bin/perl
use strict;
use warnings;
use lib '/home/me/project/temp';
use Lens;
[download]

In '/home/me/project/temp' are Cloud.pm:

package Cloud;
use strict;
use warnings;
1;
[download]

and Lens.pm:

package Lens;
use strict;
use warnings;
use lib '/home/me/project/temp';
use Cloud;
our @ISA = qw(Exporter Cloud);
1;
[download]

Apart from the recommended strict and warnings, all</code> is necessary.