Why the size of combined PDF is bigger than the originals files?
Depending on the PDF Documents to combine, the process to merge the ressources are not optimized enough. Futur versions of DirectPDF should help to reduce the final size.
Where can I get directPDF.dll and zlib1.dll?
You can get it by downloading DirectInstall.exe (http://directpdf.free.fr/download.php), which should install DirectPDF.dll and zlib1.dll in C:\WINNT\system32. It registers the COM Component DirectPDF too.

non professional web site. All brands and logos presents on this web site are only owned by their owner.