truetype font problem

Hi all,

I have problem with the truetype font. I want to open a PDF and add 
some texts, then save it as a new file.

I am required to use true-type 'Futural' font LTe50186.ttf, 
LTe50154.ttf and LTe50152.ttf.

If I use these font to create a brand new pdf file with API2, it 
works well.

If I use them with my existing program I got "Unable to extract 
embeded font ... ...". None of those fonts are working.

So I write a simple program. It's funny that LTe50186.ttf and 
LTe50154.ttf work in the following little program, but LTe50152.ttf 
doesn't seem to work at all, (I even cannot open the output 
Blank_.pdf). 

======================================================================
#!perl

use PDF::API2;

my $pdf = PDF::API2->open("Blank.pdf") || &ErrorMessage ("unable to 
open pdf");
$page = $pdf->openpage(1);
my $txt = $page->text;
$txt->textstart;

my $fnt = $pdf->ttfont('font\LTe50154.ttf'); 
$txt->font($fnt, 10);
$txt->translate(5,10);
$txt->text("LTe50154.ttf");

my $fnt = $pdf->ttfont('font\LTe50152.ttf'); 
$txt->font($fnt, 10);
$txt->translate(5,20);
$txt->text("LTe50152.ttf");

$txt->textend;
$pdf->saveas("Blank_.pdf");;
$pdf->end();
======================================================================



Thank a lot.