You thought it was your lucky day when you found that online library of BVH motion files on the web. You downloaded them all but when you loaded them into Poser you found to your dismay that they all placed the figure in the floor, or had it rotated 90 degrees or some such. You need to edit the body position by a set amount in every frame. If there are more than 20 frames we're sure you are less than happy with the prospect. Here is how to do it with just a few mouse clicks. (5-20-2007 We've added another example in this forum post that you may wish to see also).
This tutorial will walk you through the steps necessary to animate a character and make it appear to juggle, its quite a long one and you will need to work a bit - sorry.