It looks like you added the Walk behavior, which can fight with Limb IK - both are looking for the same tags. Also the way this character was created, his legs weren't set up for walking or Limb IK, so the way they seem to be rigged here is incorrect. To start I would advise:
- removing independence from the Body group and everything inside the Pants group
- make sure a fixed handle is on the body group to pin him to the floor.
- Remove the Walk behavior. If the problem persists, remove the Limb IK behavior as well.