[Bioperl-l] Can't locate object method "start" via package "Bio::Seq::RichSeq"

[=?gb2312?B?zfXqySwgU2FuIFdhbmc=?=]

Dear bioperl-l:
 The code
------
	#!/usr/bin/perl
 use Bio::Tools::SiRNA; 
 use Bio::Seq::RichSeq; 
 use strict;

 my  $seq='ATGGGGGTGGTGGTACCCTTTATCGGAAATTTACCTGCTGCACAGGAATGTTTTCTGGTGT';
 #$seq=~s/T/U/;
 my $bio_rich_seq = Bio::Seq::RichSeq->new( -seq =>$seq , -start=>1, -end => 100);
 $bio_rich_seq->molecule('mRNA');
 my $sirna_designer = Bio::Tools::SiRNA->new( -target => $bio_rich_seq );  
 my @pairs = $sirna_designer->design; 
 foreach my $pair (@pairs) {      
	my $sense_oligo_sequence = $pair->sense->seq;     
	print  $sense_oligo_sequence;
	my $antisense_oligo_sequence = $pair->antisense->seq;     
	# print out results      
	#print join ("\t", $pair->start, $pair->end, $pair->rank,  $sense_oligo_sequence, $antisense_oligo_sequence), "\n";  
  }
 
 ----

Can't locate object method "start" via package "Bio::Seq::RichSeq" (perhaps you forgot to load "Bio::Seq::RichSeq"?) at D:/Tools/perl/site/lib/Bio/Tools/SiRNA.pm line 263.

	Best Regards!
 				
			Yours sincerely
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ÍõêÉ, San Wang
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡bsman at tom.com
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡2004-03-07
 ,-,-.     ,-,-.     ,-,-.     ,-,-.     ,-
/ / \ \   / / \ \   / / \ \   / / \ \   / /
     \ \ / /   \ \ / /   \ \ / /   \ \ / / 
      `-'-'     `-'-'     `-'-'     `-'-'  


San Wang
Dr. Student
Bioinformatics and Gene Network Research Group
Zhejiang University
P.R.China

Address:
Room 415# ,Bio-technology Institute,
Zhejiang University,
Kaixuan Road 268#  Hangzhou
Zhejiang, P.R.China
310027

Tel:
0086-571-86892051
Fax:
0086-571-86961525
E-mail:
bsman at 163.com
Website:
http://www.estarray.org 

£­£­£­£­£­£­£­£­£­£­
  Innovation is everything. When you are on the forefront, you can see what the next innovation needs to be? 
			--- from Robert Noyce, Founder of Intel
  The more things change, the more they stay the same!
  The more things seem to be complicated ,the more they are simple in fact!