sorry for the trouble.
We have changed to a new installer technology for PDFCreator 4.0 and above, but the legacy setups are still available while we work on adding back command line switches for the new setup.
You can find the 4.0.3 legacy setup here: http://download.pdfforge.org/download/pdfcreator/PDFCreatorLegacy-stable
If you are using PDFCreator Free and your computer is part of a domain, the silent install has been disabled after version 3.2.2. In some unfortunate cases, the computer might get incorrectly detected as being part of a domain, which we are still investigating.
If you are using a business edition and would like to deploy silently, we recommend using the MSI packages instead.