The shining coloured lines are things that look nice but have no substance. Robots are similar in that they look like people, but they aren't people inside. So this dream could be about appearances, and how things the same on the inside as on the outside

The girl wanting to be one of the coloured lines has to do with the idea of thinking that you want something, without realising what that thing really is.

Your sister stepping over the CD could also refer to this, as a CD is a recording of music, not the original music, in a way it's an illusion itself. Your sister stepping on the CD is destroying the illusion.

So the dream may be trying to tell you to look at the reality behind things, not just the surface of things.