I got png fireworks with layers from job to slice. I have only Photoshop, but they said I could open it in Photoshop. I try to open this but, I have only prompt: "This PNG contains additional data for Adobe Fireworks, which will be discarded upon save" and image was flatten. My photoshop version is: CS5 v12.1 x64.
A normal PNG cannot contain layers, and Photoshop will be unable to save it with layers. Your only option is to save it as a PSD or use Fireworks.