Hey when i try rotate something, the quality drops very much, why? It is normal? http://i68.tinypic.com/ddgi12.png
How rotate without this..bug?

How are you rotating the image? If you're doing that with the transform tool, yes, you wiil get degratation. If you just rotate the canvas, no, it shouldn't degradate.

I'm assuming you mean rotation with the Transform Tool. What filter algorithm have you selected? Lanczos3 for example gives a sharper result with blending; Nearest Neighbor disables any color blending, which is useful for pixel art.

Also keep in mind the preview of a transform shows a lower quality than what the result is when you apply it.