file type not supported or pfd-file is corrupted

Hi, I get the above mentioned error message as soon as I would like to open the generated file with Acrobat Reader. I am using 2.4.2 version of this extension. Versions prior to that do not even generate a file. Help would be cool. Cheers

[[kgh]]‎

I have the same problem. Using the following environment:
Windows XP Easy PHP 5.3.1.0
MediaWiki 1.16.4
PdfBook Version 1.0.4, 2010-01-05
HTMLDOC 1.8.27