DT Max help file not displaying topic in right-hand side pane

When I open the DT Max help, why does the HTML Help viewer display the error message "Action cancelled" in the topic pane instead of displaying the desired topic?

Microsoft's Security Update 896358 restricts execution of HTML Help files to the local machine. To correct the problem, select one of the two alternatives below:

A - Install the DT Max knowledge base files (.CHM) on the local drive (preferably in the default installation directory C:\Program Files\DT Max\KB\).

B - If you prefer not to install them locally, you must re-enable the execution of HTML Help files for the "Local Intranet" zone.

We have compiled the fix into a registry excerpt that you can download and install with a simple double-click of the mouse.

1. Download the file, unzip it then save it.

2. Open the file "DTMaxKB_FIX.reg" on every computer concerned. Windows will merge the registry setting contained in this file into the registry of the computer.

You must perform these steps on every client computer in your organization in order to enable HTML Help for your office.

More details on this topic are available in this Microsoft knowledge base article.