It's not really d-links fault but Apple changed the way AFP worked in Lion and Mountain lion (to make it more secure so they say), ever since Apple upgraded their AFP protocol time machine has been broken for me. As far as I am aware D-link have never upgraded support for the new AFP method, but it will still work with the older mac OS.
I won't be buying d-link again to be honest, they are low priced for a reason, the support is poor and they are slow to fix anything, if they fix it at all. Apple moved the goalposts, fair enough but d-link seems to just choose to leave you stuck if that happens. To get better support you have to spend a bit more I think, I learned my lesson thats for sure.