Remote Task Servers are not registering correctly. Numerous 'Unable to Register' messages are in the agent.log files of the remote Task Servers.
Further research revealed that none of the Task Server virtual directories were available in IIS.
The Task Server portion of the Altiris Web in IIS was not installed. When the option to remove HTTP codebases was selected in the NS console for the Package Servers, the Package Server removed everything under the Altiris virtual directory, including all Task Server components.
Workaround: Repair Task Server from the ADD/REMOVE programs applet, and then restart IIS, the Altiris Agent, and the Altiris Task Server services.