the x3 710 isnt a problem, it will work in both am3 and am2+ mobos, you can rest assured Trotter knows what hes talking about
yes, the x4 940 will work with your mobo. the cpu magazine is just a gift bundled with the cpu. its basicly what it says it is, a magazine. i dont know whether its just one issue or a subscription, dont worry about it.
about your problem, did the 710 not work at all from the beginning, or did it work for some time? i ask because maybe you need to flash the mobo's bios for it to work, which isnt uncommon, sometimes the boards just come like that from the factory, with an older bios verison.