A: d3d9.dll is the Direct3D component of DirectX 9. MooPlayer requires this to function (as stated by the system requirements). In order to give MooPlayer the functions I wanted it needed access to a feature added in Windows XP and made available to all versions of Windows (well, not 95) when DirectX 9 was released. Hence this requirement...

A: Make sure you have a DirectX 9 driver for your card. That means Catalyst 3.0 for Radeon and Detonator 43.45 for GeForce.
There is also an issue with Catalyst 3.1 and 3.2 that can cause heavy CPU usage. Not much I can do about that. Use another driver...

A: Same problem as above.

A: This is a bug in the Windows Media CODEC. Early versions of it doesn't work properly with the new VMR. The Windows Media 9 CODEC is known to work.

A: Microsoft at its finest again I'm afraid. The old Windows Media CODEC identifies some DivX as WMA:s and tries to decode them, of course with little success. Get Windows Media 9 and you should be fine.

A: The CODEC pack which you can get from Windows Update seems to be a bit of a placebo. No new CODECs are installed (no working at least). In order to get the CODECs you need to install either Windows Media Player 9 or Windows Encoder 9.

A: Some CODECs are locked to only work in overlay mode and fails to detect situations where it cannot function
in this mode. Applications like Windows Media Player doesn't suffer from this (since they use overlay mode) but MooPlayer does.
Most CODECs can be forced into normal mode though. Ligos MPEG-2 CODEC has an overlay setting and DivX is forced into normal mode by enabling double buffering.
If you have found another CODEC with this problem (and possibly a solution) then please send me a mail.

A: Because you don't give me enough questions to make them frequent! Start populating the forums dammit! ;)