Animation from blender weridness

[Juras]

When vertices go crazy like that it usually means that the weights are not normalized. That would be the first step to do on your rigged mesh. I don't use blender for animation and rigging so I don't know where you would do that but I'm sure the is an option for that somewhere in the software.

Also make sure that you're using the FBX format. If I'm right, Blender .dae format doesn't work so well with HPL2.

Lastly, you don't want to export the animations with mesh data, you only need the skeleton data. You only need the rigged mesh fo the mesh data (which also includes the skeleton data), that's the base for animations. If you're rigged mesh is exported correctly then you won't have to worry about problems like this in your animations.