Dear monks, I am trying to write a simple script to align 2 sequence objects. The problem is that I get the following error message: Use of uninitialized value in concatenation (.) or string at C:/Perl/site/lib/Bio/Tools/Run/Alignment/Clustalw.pm line 645. Use of uninitialized value in concatenation (.) or string at C:/Perl/site/lib/Bio/Tools/Run/Alignment/Clustalw.pm line 646. 'align' is not recognized as an internal or external command, operable program or batch file. I would really appreciate some help. Here is my code.

#c:\perl\perl.exe 
use strict; 
use warnings; 
use Bio::Seq;
use Bio::Tools::Run::Alignment::Clustalw; 

BEGIN { $ENV{CLUSTALDIR} = 'c:/CLUSTALW2/' } 

my $dna_seq = "NACCNANCGGGGGNNAAANTNNNACACTNCNGGGGGGNTNNTTANTGNGTNACAC
+ANNNGNCTNNNGGNNNCNANANTCNACAG +GACTTAGAAGNCTNCANNGGANCATNCCCTGCTANACN
+ANGNNANCACTCTNCAGNNCNNANCNTNGGGCNNCCTNNTCNNTNNNCCATNNGNGCTNC +ANNANCN
+TANANNGATNANTANAGNANNTTNTGTTATGNNGNGTG"; 

my$tn5_seq = "GGGGNCCCGCTTACGATACTTCGTTATAGCATACATTATACGAAGTTATCAGATCC
+CCCTGGATGGAAAACGGGAAAGGTTCCG +TCCAGGACGCTACTTGTGTATAAGAGTCAGGTT"; 

$dna_seq =~ s/\s+//g; 
$tn5_seq =~ s/\s+//g; 
my $id_1 = 'test1_DNA'; 
my $id_2 = 'test2_DNA'; 
my $alphabet = 'DNA';
 
my $seq_obj = Bio::Seq->new(-seq => $dna_seq, 
-display_id => $id_1, 
-alphabet => $alphabet); 

my $tn5_obj = Bio::Seq->new(-seq => $tn5_seq, 
-display_id => $id_2, 
-alphabet => $alphabet);
 
my @params = ('ktuple' => 2, 'matrix' => 'BLOSUM'); 

my $factory = Bio::Tools::Run::Alignment::Clustalw->new(@params); 
my @seq_array =(); push @seq_array, $seq_obj, $tn5_obj;
my $seq_array_ref = \@seq_array; 
my $aln = $factory->align($seq_array_ref);
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