If I try to bend, twist or back-and-forth any of the arms and legs in any of the P4 or P5 characters(i.e. Gabrielle, Monique, Holly, etc.) too far, the joints(i.e. elbows, wrists, knees) look like the appendages broke off and someone glued them back on crooked. Is there a way to avoid or fix this problem?

Are you dragging them to pose? The dials work much better if that is the case.

Also for better results don't forget to put 'use limits' turn on...and if you pose use 'auto balance' It might help...

Turn off IK, too. It makes some of the joints spin like crazy, without actually altering the pose.

Some of this is just a limitation in the posing abilities of Poser figures. Poses that are simple for humans (like touching your mouth) cause mesh breakages in Poser 4 figures and I'm not sure how much better the P5 ones are.

If they go all pretzel-y, turn off IK and return all the bend/twist/side parameter dials for the affected part to 0 and start over. I use IK only for fine-tuning--putting the hands right where I want them, getting the hip bend/rotation just right without sending the feet flying. Limbs often have to be posed in increments to get them where you want them to go--first shoulder, then forearm, then hand (or bettock, thigh, shin and foot). Lots of people forget to pose the buttock--a must if you're bending legs/hip much more than a few degrees. Dang, I should do a tutorial.