difference between same colores shapes

[Sihm]

We are a group of five starting on the animation-part of a short animation.

I tried to put the character into Anime Studio, this is my first time using the software.
But there is a problem between layers that has the same color, I can tell the difference between the layers. I would love to get rid of this.
Here is my two tests:
http://vimeo.com/38220035 look at his pants

I know it's a very small difference, but it needs to be solved, so we don't get surprized when we see it on a big screen http://vimeo.com/38219183

It's just PNG-files, i exported from photoshop.

Do anyone have any good advices?

Kind Regards Pernille