System error

error:  Can't call method "selectrow_hashref" on an undefined value at /var/www/seminars/seminar.html line 9.
context: 
... 
5:  <%init>
6:  use DBI;
7:  my $dbh = DBI->connect("dbi:Pg:dbname=hefesto;host=saturno.tng.iac.es", 'hefesto', 'hefesto');
8: 
9:  my $seminar = $dbh->selectrow_hashref("
10:  SELECT seminars_seminar.id, seminars_seminar.title, seminars_seminar.datetime,
11:  seminars_seminar.abstract, seminars_speaker.name, seminars_speaker.affiliation,
12:  seminars_seminar.presentation
13:  FROM seminars_seminar
... 
code stack:  /var/www/seminars/seminar.html:9
/var/www/seminars/autohandler:5
/var/www/autohandler:134
raw error






























Can't call method "selectrow_hashref" on an undefined value at /var/www/seminars/seminar.html line 9.


Trace begun at /usr/local/share/perl/5.8.8/HTML/Mason/Exceptions.pm line 129
HTML::Mason::Exceptions::rethrow_exception('Can\'t call method "selectrow_hashref" on an undefined value at /var/www/seminars/seminar.html line 9.^J') called at /var/www/seminars/seminar.html line 9
HTML::Mason::Commands::__ANON__('id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Component.pm line 135
HTML::Mason::Component::run('HTML::Mason::Component::FileBased=HASH(0x960a9ac)', 'id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 1256
eval {...} at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 1246
HTML::Mason::Request::comp(undef, undef, undef, 'id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 915
HTML::Mason::Request::call_next('HTML::Mason::Request::ApacheHandler=HASH(0x86a2a7c)') called at /var/www/seminars/autohandler line 5
HTML::Mason::Commands::__ANON__('id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Component.pm line 135
HTML::Mason::Component::run('HTML::Mason::Component::FileBased=HASH(0x960b060)', 'id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 1256
eval {...} at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 1246
HTML::Mason::Request::comp(undef, undef, undef, 'id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 915
HTML::Mason::Request::call_next('HTML::Mason::Request::ApacheHandler=HASH(0x86a2a7c)') called at /var/www/autohandler line 134
HTML::Mason::Commands::__ANON__('id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Component.pm line 135
HTML::Mason::Component::run('HTML::Mason::Component::FileBased=HASH(0x81fd1a8)', 'id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 1251
eval {...} at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 1246
HTML::Mason::Request::comp(undef, undef, undef, 'id', 6) called at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 460
eval {...} at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 460
eval {...} at /usr/local/share/perl/5.8.8/HTML/Mason/Request.pm line 412
HTML::Mason::Request::exec('HTML::Mason::Request::ApacheHandler=HASH(0x86a2a7c)') called at /usr/local/share/perl/5.8.8/HTML/Mason/ApacheHandler.pm line 168
HTML::Mason::Request::ApacheHandler::exec('HTML::Mason::Request::ApacheHandler=HASH(0x86a2a7c)') called at /usr/local/share/perl/5.8.8/HTML/Mason/ApacheHandler.pm line 826
HTML::Mason::ApacheHandler::handle_request('HTML::Mason::ApacheHandler=HASH(0x87e2b24)', 'Apache=SCALAR(0x86a2e18)') called at (eval 33) line 8
HTML::Mason::ApacheHandler::handler('HTML::Mason::ApacheHandler', 'Apache=SCALAR(0x86a2e18)') called at /dev/null line 0
eval {...} at /dev/null line 0