PDFFORGE.DLL causes app to crash on Win 8.1

An app written in Delphi uses pdfforge.dll to rotate pages in a pdf file. While the app works without problems on Windows 7 and Windows 10, it crashes on Win 8.1 at the very moment where RotatePages() is called. Crashing means, Windows kicks the app out of memory saying “The application caused an error and Windows had to stop it”. No exception is thrown, no error message, nothing. It just dies. Before calling RotatePages(), the DLL/COM access is checked calling pdfforge_TLB.TDllInfo.Create(Nil).Version which returns the version successfully. So there should not be a registration problem.
Any idea on what might cause the PDFFORGE.DLL to crash that heavily when running on Win 8.1 (32 bit).
The version is
Thank you very much!