As some of us already know, Mixamo no longer stores models and animations online for us, but we can still download the FBX geometry with animation. I generated several FBX files from Mixamo and tried to get them inside Poser Pro 11. The figure comes in horribly twisted, and even BVH Helper (an add-on utility) appears not to be able to fix the problem. There is a solution:

1. Launch Blender 3D (I am using version 2.78c), and delete the default cube
2. Import the Mixamo FBX file into Blender, and select it in the scene contents hierarchy.
3. Export the FBX as a differently named file (use the default export options; they seem to work fine)
4. Close the Blender scene and start a new one - this is very important. (If you merely delete the content which you imported, and import a fresh Mixamo FBX file, Blender remembers the older file and you won't be able to export the next FBX file).
5. Launch Poser Pro 11 (latest version at this time).
6. Import the FBX file you had exported from Blender. Geometry scale = 100% is fine.
7. Trim the animation of the figure so that you get a looping motion.
8. Export as FBX (Poser defaults are fine). Make sure you export all the frames you need for the looping animation, when Poser prompts you during the export process.
9. Save as a different filenamed FBX.
10. Finish.