I've just spend four months trying to figure out what I was doing wrong (or where the bug is), and I believe I've discovered what it takes to actually make this work.
First, you've got to be using Acrobat Pro.
Second, you've got to turn on Preferences ... Catalog ... Allow Catalog Batch Files to be Run
Third, you've got to create the "bpdx" file with the following format:
<fully qualified path to .pdx file> /rebuild
(for example, one line in the file, as "C:\Users\Adam\Documents\index.pdx /rebuild") -- IT IS VITAL that the fully-qualified path, even if it includes spaces, is not enclosed by quotes. That is, use
C:\Users\Adam\Documents\This Is An Index.pdx /rebuild
not
"C:\Users\Adam\Documents\This Is An Index.pdx" /rebuild
You can make sure this is set up properly at the command-line:
C:\Users\Adam\Documents>"c:\Program Files (x86)\Adobe\Acrobat 11.0\Acrobat\Acrobat.exe" c:\Users\Adam\Documents\rebuild-index.bpdx
Then:
Fourth, set up a scheduled task using Windows Scheduler, making sure the program/script is Acrobat, and the arguments is the path to the bpdx file:

Scheduled index updates (Acrobat Pro)![]()
Use the Catalog feature and a catalog batch PDX file (.bpdx) to schedule when and how often to automatically build, rebuild, update, and purge an index. A BPDX file is a text file that contains a list of platform-dependent catalog index file paths and flags. You use a scheduling application, such asWindows Scheduler, to display the BPDX file in Acrobat. Acrobat then re-creates the index according to the flags in the BPDX file.
For more information on scheduling an indexing update, search for BPDX atwww.adobe.com/support.
Note:
To use BPDX files, in the Preferences dialog box under Catalog, selectAllow Catalog Batch Files (.bpdx) To Be Run.