5D was taken over by Jaws Systems earlier this year.
There was a loop-hole which allowed those with a serial number from the ctrlp software to have a "free" version of the upgraded "Jaws" software. Jaws seems to have become aware of this after a couple of weeks of the release of the updated software hence the current state of affairs at the Ctrlp website.
The Jaws software of version 2 compared to Ctrlp's version 1.
I think that the best way around this is to look for other "free" pdf creators as there is no longer a free version of this particular software. Having said that, even if you chose to buy "Jaws", it is still hugely less expensive than Acrobat

I don't know, however, if the work-around to get the free Jaws software still works, but take this to email if you want to discuss it more fully with me.
I have, and still occasionally use, GhostScript/GhostView from Aladdin software. This is free for personal use. A web-search for "Ghostscript" will do the trick. You will also need to install a driver for a "postscript" printer. GhostScript/View works on PS files so you need to make one before converting this to the PDF.
I use the HP LaserJet 4050 PCL6 PS driver available for free download from the HP site (for so long as they remain HP!). Seems reliable enough but it is a two-stage process to create a pdf.
Cheers
John