You appear to be trying reference the hash symbolically, where as you need to store a reference to the %other0 hash to get your code working e.g

use strict;

my (%other0, @catnames);

%other0 = (
    'cat0' => 'a string',
);

## create reference to %other0 hash
@catnames = (\%other0);

print "access hash: ", $catnames[0]->{'cat0'};

__output__

access hash: a string
[download]

See. perlreftut and tye's References quick reference for a couple of good starters on references.
HTH

_________
broquaint