The following code works. You need to define the media size and the font on the 2nd page.

#!/usr/bin/perl -w
use strict;
use PDF::API2;

my $pdf=PDF::API2->new; # Create a new top-level PDF document
my $font = $pdf->corefont('Helvetica');

my ($page, $text);

$page=$pdf->page();        # Create 1st page
$page->mediabox(500, 700);  # Set the page dimensions
$text=$page->text();
$text->translate(50, 650);  # Position the text
$text->font($font,12);
$text->text("Page 1");

$page=$pdf->page(2);         # Create 2nd page
$page=$pdf->openpage(2);
$page->mediabox(500, 700);  # Set the page dimensions for 2nd page
$text=$page->text();
$text->font($font,12);      # Set font on the 2nd page
$text->translate(50, 640);  # Position the text
$text->text("Page 2");

$pdf->saveas("file.pdf");
$pdf->end;
[download]