Had similar issue on my Ds45, found out that the back of my foot had rubbed against the speed selector lever and turned it all the way to slow. When I repositioned the lever to midway - low and behold the pto started functioning, easy fix for me - best of luck to you.
My ignition switch has stopped killing the engine, I have to use the manual fuel cut off to kill the engine. What do I look for to correct the problem?