The Line6 presets (at least for bass) are considered rather bad. Personally, I use only a few presets that I customized, and none of the factory presets.
Still, as I recall, Line6 has some sort of on-line preset bank, where customers share their presets. Since you have the better-supported guitar PODxt (support for the Bass PODxt is pretty bad), you shouldn't have any trouble.
Try this:
http://line6.com/customtone/help/installation.html