Note - you can still download CCDsoft V4 from Software Bisque and use it unregistered for free - but with no support. I don't know if V5 offers a whole lot more than V4, but maybe its worth a gander!
If you simply register with the site for access to free download, you can access archived and free programs. CCDSoft v4 is in the archived (unsupported) section and weights in at 10.5 MB file. If you download it, run instal and enter any serial number e.g. 123456 will do and it will install and run fine.
I e-mailed this to the guys at SB weeks ago - and no reply so I presume its a designed feature. I use Adobe Photoshop CS2, and after reading about the Zone System I simply wanted to try a 30 day trial of CCDSoft but found V4 was archived and available as an interim until you upgrade.