The Scheduler should work for HoMM III 4.0 and HoMM II 2.1 (but not for HoMM III 3.2)
I only tested it on the Complete Collection from Buka, but I don't see any reason why the program shouldn't work for the English 4.0 version as well.
Please let me know if it doesn't work for anyone. I tested it on three different computers - it works.
Added 23 minutes later
Also, be sure to restart the Traffic Light if you exit the game!
Also, check the executable name. It should be heroes3.exe
P. S. If you don't need the Traffic Light, but you want to use the MP Monitor or the Development Scheduler, just ignore the "Address not found..." message (the address is only needed for the Traffic Light to work). I also tested the Monitor and Scheduler under MS Windows Vista Ultimate SP 1 - they work without problems (and should work). The Traffic Light didn't work even for me. Apparently, it is necessary to unambiguously determine the R address, which I will try to implement in the next version.