problem with dia 0.92.2 & Fedora Core 1

[jerome moliere <jmoliere nerim net>]

Hi all,
using the above configuration,  I 'm facing a small problem with DIA...
I'm writing a book using docbook & I use FOP transformation to get a PDF 
from my docbook files..
So I must use PNG format to get a proper rendering (in the final PDF)...
I read the manual & check the FAQ but can't find any information about:
why can't I get any file exported when doing export (file menu after 
right click) & selecting PNG format ?
my dia file is written no problem but I'm unable to get a PNG version .. :(
very boring for my work...

Thanks for your help
Jerome

-- 
Auteur cahier du programmeur Java tome 2 - Eyrolles 10/2003
http://www.eyrolles.com/php.informatique/Ouvrages/ouvrage.php3?ouv_ean13=9782212111941