Please use code tags around your code...

What about something like this:

#! /usr/bin/perl
use strict;
use warnings;

while  ( my $line = <DATA> ) {

   my $count = $line =~ tr/AEIOUaeiou//;
   print $count, $/;
}

__DATA__
no
ah, two...
ave
ave caesar
[download]

Please read additionally at perldoc -q count

Updates

1. expanded code to show a complete working example
2. $code =~ s/cnt/count/g