Does it produce an error message? Maybe try looking at what the expression is returning before trying to dereference it:

   my $ref = $XML->{output}('name','eq',"$show");
   use Data::Dumper;
   print Dumper($ref);
[download]

Maybe what you see will make it obvious why your code isn't working.

-sam

PS: You might also consider finding another XML module. XML::Smart is interesting, but it's not exactly part of the Perl XML processing mainstream.