Automatic directory changes don't work at all

I'm using TCMD v13.04.63 and have found that automatic directory changes don't work at all. All I get is "TCC: (Sys) The system cannot find the file specified."

I have run cdd /s to index the drives, and jpstree.idx exists in the root of drive C: I have checked the file and all the folders are listed, but cdd <foldername> cannot change to any of them (unless that folder exists in the current directory, which means that cdd behaves no differently than cd). For instance, "c:\> cdd windows" works. But "c:\> cdd system32" doesn't work. It's just not doing the extended directory search and can't use wildcards either.

It's not a feature I use all that often, but it used to work. I have a feeling that I am overlooking something blindingly obvious. Anyone know what it is?
Automatic directory change works based on the value of your CDPATH environment variable. Look it up in HELP! The feature works as alway here (WinXP SP3/32b, TCC 14.03.52)
CDPATH only works for an explicitely set list of directories. I am talking about Extended Directory Search which is supposed to work on the entire drive(s) (provided they have been indexed).