Hi there,
I just went out and bought a new Logitech "Rumblepad2" gamepad. I've installed the most recent drivers for it, and the Feb2006 DirectX SDK. In the control panel -> Game Controllers I can get it to rumble without a problem, so it does work. In there its possible to test at least 10 different rumble effects. I'm developing in VS2005/WinXP Pro.

When I tried the MSDN example of force feedback (located here: http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_m_Oct_2004/directx/input/directinput_forcefeedback.asp)
it flops. First problem with that example is you need a "force feedback effect file" which is nowhere to be found in the current SDK. After searching the web it seems it seems fedit.exe was used to create it, but that is nowhere to be found either (apparrently it was only included in the Summer '04 sdk). Anyway, I got the last example to compile, but it still does not work. It throws an argument exception at the eo = new EffectObject(...) line.

This was previously mentioned in this post: http://forums.microsoft.com/msdn/showpost.aspx?postid=112192&siteid=1
and it still has not been fixed yet.

Below I've included my stripped down code example with the hope that someone can get this to work. Thanks in advance :)

Code:
private void button1_Click(object sender, EventArgs eventArgs)
{

DeviceList dl = Manager.GetDevices(DeviceType.Joystick, EnumDevicesFlags.ForceFeeback);
Guid guid = new Guid();
foreach (DeviceInstance di in dl)
{ // grab the guid for the device (only have 1)
guid = di.InstanceGuid;
}

Device gamepad = new Device(guid);
gamepad.SetCooperativeLevel((Control)this, CooperativeLevelFlags.Exclusive | CooperativeLevelFlags.Background);
gamepad.Acquire();
EffectObject eo = null;
Effect effect;

foreach (EffectInformation ei in gamepad.GetEffects(EffectType.All))
{ // find the constantforce effect
if (DInputHelper.GetTypeCode(ei.EffectType) == (int)EffectType.ConstantForce)
{ // found it, so set the effect type
effect = new Effect();
effect.EffectType = EffectType.ConstantForce;
eo = new EffectObject(ei.EffectGuid, effect, gamepad); // ArgumentException: Value does not fall within the expected range.
}
}
}