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?