Did you installe the Developer or End User version of the PDF Converter?
Did you activate the printer when installing it?
Please note that when using the PDF Converter from inside your application you need to call EnablePrinter right after calling DriverInit for the printer to get activated.
You need also to call EnablePrinter right before printing.
You will find the Activation Code to be used as parameters for EnablePrinter() in a file called Install.ini that got created on your system (in the same folder as the Converter) when installing the PDF Converter
Hope this helps.