32-bit shell extensions do not work on 64-bit machine

The context sensitive menu items such as purge and salvage, as well as the Novell-specific tabs in the folder properties page, do not appear when accessing these in a 32-bit application on a 64-bit machine, but they do show up on a 32-bit machine (running Windows 7 in each case).

For example, the shell extensions do appear when running a 64-bit version of Notepad (from Windows Explorer) but do not appear when running the 32-bit version of Notepad (from \Windows\SysWOW64\).