use Net::Telnet;
use strict;
my $filename;
my $obj;
my $telnet = new Net::Telnet (Timeout => 10, Errmode=>'return', Port=>1810, Prompt => '/[\$%#>] $/' );
my $fh = $obj->dump_log($filename);
my $telnet->open('PC110197');
my $telnet->errmode(sub{return@_ unless $_[0] =~ /eof/});
my @ausg = $telnet->cmd('CLIENT CREATE');
print @ausg;

use Net::Telnet;
$telnet = new Net::Telnet (Timeout => 10, Errmode=>'return', Port=>1810, Prompt => '/[\$%#>] $/' );
$fh = $obj->dump_log($filename);
$telnet->open('PC110197');
$telnet->errmode(sub{return@_ unless $_[0] =~ /eof/});
@ausg = $telnet->cmd('CLIENT CREATE');
print @ausg;

Can't call method "dump_log" on an undefined value at prog.pl line ....