I have two controllers with rumble. I can make them rumble with other apps. When I click the 'motor' button in the controller config for either controller, many options appear in the list that it detects the controller has. The test button will simply not make them rumble though and they will never rumble in games if you select a motor either.
CPU: Intel Core i7 920 @ 2.67GHz
GPU: NVIDIA GeForce GTX 285
RAM: 6 GB
OS: Windows 7 Ultimate x64
GPU: NVIDIA GeForce GTX 285
RAM: 6 GB
OS: Windows 7 Ultimate x64