how about

use strict;
use warnings;

my %saw = ();
while ( <DATA> ) {
    next unless ( m#^M.*/([^/]+)# );
    my $filename = $1;
    chomp $filename;
    $saw{$filename} = 1;
}

print "People not found\n." unless ( $saw{'people.pdf'} );
print "animal not found\n" unless ( $saw{'animal.pdf'} );
print "MSI file not found\n" unless ( $saw{'setup.msi'} );

__DATA__
M/people.pdf
M/wiggles.pdf
M/setup.msi
[download]

You do twice as many "if"s as necessary: just store everything and do the checks once.

- doug