Unable to downdate

I have a installation setup from a specific piece of software that includes an older version of PDFcreator (v1.5 ?). After a update to 2.5 the accompanied software refused to output PDF due to a incompatibility issue with 2.5. So no harm done I thought, just put the old 1.5 back and no worries. But unfortunately, no sigar. ReRunning the software’s setup resulted in a error while installing the 1.5 PDFcreator. The setups logfile shows the following error:
Printername: PDFCreator
Drivername : PDFCreator
Portname : pdfcmon
Result: Error 1796 = The specified port is unknown

Does anyone know how to reinstall the old version?
thanx in advance.


if the problem is related to the current version not getting unistalled properly we can help.
Is there currently still a pdfcmon.dll in C:\windows\system32?
Which software is using the outdated PDFCreator version ? We’d like to contact the manufacturer to see if it is possible for them to use an up-to-date PDFCreator version.

Best regards,