for my $directory (@directories) {
        # read all subdirs
        $hierarchy{$directory} = ();
        opendir DIR, $directory;
        for my $filename (readdir DIR) {
            # remove filename extension
            ($filename) = split('.', $filename);
            print $filename;
            push($hierarchy{$directory}, $filename);
        }
        closedir DIR;   
    }        

##</code><code>##

Type of arg 1 to push must be array (not hash element) at
admin.pl line 230, near "$filename)"