You should provide the code where you are trying to collect the values of the hash. It is very hard to find one's error until the code is remaining hidden.

Here is a tip until you do that:

#!/usr/bin/perl

use strict;
use Data::Dumper;

convert (
'MIME-Type' => 'application/ms-word',
'Input' => '[In file]',
'Output' => '[Out file]'
);

sub convert {
    my %hash = @_;

    # show the full thing
    print Dumper(\%hash);

    # or just one value
    print $hash{'Output'},"\n";
}
[download]

I prefer passing hashrefs though...