Hi,
I have the exact same issue.
I have 2 DHP-307AV which works perfectly, and I have added a DHP-W306AV to have a better wireless.
First unit worked fine for about a year, but suddenly stopped working... (seemed to overheat too).
After some discussions with dlink support, they asked me to send the unit back and they sent me a new one.
Got this one about a week ago, and it worked for 15 mins!
Now, it is getting very hot whenever I switch it on and after 5 mins it looses the CPL sync.
I am very happy with the DHP-307AV but I am seriously considering switching brands now that I cant get the wifi unit to work...
Santhy.