foreach (@files) {

  my $FH = $_;

  open (FILE, "<$FH"); 

  
 OUTER: while ((my $line_B = <FILE>)) {

    last OUTER unless defined($line_B = <$FH>);  ## The message applies to this line

    my $batch;
    
    do {
      
      $batch .= $line_B;
     
    } until ($line_B =~ m/^\s*go\s*$/i);
    $dbh->do($batch) if ($line_B =~ m/^\s*go\s*$/i);

  }

}