getting ImageMagick to work with vB (on Windows)

[Psalmist]

I'm running vBulletin on a windows server. I changed the Image Processing Library setting in vBulletin from GD to ImageMagick.

But now when I try to upload an avatar (as a user, under "Edit Avatar" in the User CP), I get this vBulletin Message: "Invalid File".

When I installed ImageMagick on my server, I had two different installation packages to choose from, the DLL version and the static version:

ImageMagick-6.4.7-2-Q16-windows-dll.exe
ImageMagick-6.4.7-2-Q16-windows-static.exe

I chose the DLL version (since it was the recommended one).

Is that the problem?

If it matters, the ImageMagick Binary Path I set is:
C:\Program Files\ImageMagick-6.4.7-Q16\

(And that is indeed the path to the program folder for ImageMagick.)

(I know that ImageMagick is working on my server because I did their test to verify.)

So in short, my question is, which version of ImageMagick should be installed (on Windows)? The DLL or the Static? Or does it matter?

Thanks