#!/usr/bin/perl -w
use strict;
use Data::Dumper;

...

while ( my $line = <STDIN> ) { # No need to declare $line until here.
    my @AA = $line;            # No need to declare @AA until here. 
                               # Might need to split the line, though ...

    print Dumper \@AA; # See what's really in that array. Note the backslash.

    ...