We derive theoretical bit and frame error rate expressions for decode-and-forward (DF) collaborative networks containing M users, employing a variety of block codes over a Rayleigh block faded channel. With the aid of these expressions, we explore the performance of adaptive power control for such systems. This extends previous work by optimizing power allocation for all relay and direct channels. We further extend our work to a variety of cooperation mechanisms and we conclude that power control can greatly benefit a DF collaborative network in a fading environment.