Disruption when walking under the dress?

Hi. Please use google translate for the future so that more people would be able to understand the problem

You should transfer weights and uv_1 from the dress of the same length (or a bit longer) and use Nearest face interpolated in the settings.
The problem you're witnessing mainly lies in the fact that the reference was too short and the bottom of the dress received the data from the legs instead of the dress.
The dress is also not vertex painted the right way.
- in uv editor enable sync, select all uvs of the dress, in 3d view press P, choose Selection to separate;

- select the separated dress, in edit mode select everything with A, Remove doubles;

- do not scale uv islands individually unless the difference in the texture quality is acceptable. You can make the uv island of the geometry that cover the hole at the bottom of the dress smaller, but do not make some other part of the dress bigger than others, it will be noticeable. Select uv_0, select all uvs with A, UVs - Average island scale to undo this;
- select "reference", Shift-select your dress, switch to Weight paint, choose Weight transfer, set it like in the pic, then use Clean tool with All groups and Limit total with 4;

- select the dress, add Data transfer, choose "reference" as Source object, set the rest like in the pic, apply;

- transfer Vertex paint the same way

- select the body, delete all areas of it covered by clothing;
- join the body with the dress, adjust uvs in uv_0. Bigger uvs = better texture quality;
- import in the package started from DressPanels