When you apply a walk cycle to a figure, the figure will move to a position so that its hip and Body actors are above the start of the walk path. This hapens regardless of the figures position in the scene before the walk cycle was applied. So the walk paths need to be spatially seperated.

When you click 'Apply' in the Walk Designer, you will be presented with the 'ApplyWalkDialog' box. Here you can chose the figure to apply the walk to, and select which path the figure is to follow. See the image above, the box may look diffrent in your Poser version, but the principle is the same. 

To be continued...