The CDP Downloads page (hosted at
https://www.unstablesound.net/cdp.html) is currently undergoing revision.
The CDP Documentation download, in particular, is faulty and should NOT be downloaded yet. It will be fully revised very soon and I'll post a notice when it's ready.
If you do not have the current documentation, it can be downloaded at:
http://www.ensemble-software.net/CDPDocs/html/updates.htm - the full version is called CDPDocs.zip and is dated 30 Oct 2021. An update to this (to match the version on the downloads page) will be available in due course.