Oh boy, I'm pretty new to Poser, but I think I know what going on... You're asking poser to render "on the fly" and poser can't do that. You're going to have to look at each frame as a "still" (Not exactly correct, but close.) In order to see the "non-blocky" version of your animation, you'll have to render to disk, and then watch it in Quicktime or whatever.