I don't really understand what you are talking about in your post. But no worry's.. I went to Rio some years back so I had a taste of the Brazilian english level in general (No offence
)- I think you are doing just fine!
Anyway. I had a look at your scene and will try to make a few surgestions based on that.
Problem of skin not deforming good at junctions: Add more detail/edgeloops at the joint areas. Eg. Try bending a cylinder with no crosssections/Subdivisions.. very hard!
Problem of fingers being "broken": You need to edit your skin weights. If vertexes of the Index finger are weighted to joints of the middle finger they will stay with/follow those joints. With the mesh selected go : Skin>Edit Smooth Skin>Paint Skin Weights Tool and fix it there. (or use the componet editor)
Notes on setup:
The choice to use IK on the fingers seems strange to me. Try setting keys on the IK handles and then rotating the wrist - the fingertips stay where they are! Allthough it looks kind cool, it's not very handy for general animation purposes. If you want to use the IK chains on the fingers, be sure to parent then under the wrist. I would go with rotation control on the fingers, but if you find animating each finger joint to time consuming, you could make attributes like fist/fingerbend and drive the joints with these by using expresions or setdriven keys. I don't know if these terms are out of your scope right now? If they are just do rotations. (I would do stright rotations on the whole hand and avoid any(!) fancy setup's anyday)
I don't know if this is a part of a complete rig? If the rig is just this I would say that the root joint in the wrong place! The root should be at the elbow and not at the wrist. That way you can rotate the elbow and have the wrist follow and rotate the wrist without the elbow following. Also your local rotation axis on the wrist are scewed. To fix these things and the skinnig I would do the following:
Select the mesh. Go skin>detach skin options. Choose the delete history option and apply. Now select the elbow joint and go skeleton>reroot skeleton. Next unparent the thumb and pinky joint so the only child of the wrist joint is the hand joint. Select the wrist joint and go skeleton>orient joint. Reparent the thumb and pinky to the wrist joint. Now use the Split polygon tool or the Cut faces tool to add the extra edges to the geometry. When you are done select the mesh and go edit>delete by type>history. Now rebind the skin to the skeleton and paint those weights. Done.
- There are many alternatives to what i just described - this is just one way to "fix" your scene.
Whew.. someone is bored
Anyway hope you can make sense and use of all this. Hope I didn't come off too patronising! If you think my surgestions suck please let me hear your responce.