A number of people I talked to have had trouble with parts of DoD. Some people can't claim the gargoyle shroud or mount, some can't get into any monster missions, I could not get into any NeK missions (disconnected me when I tried to enter, came back half way across the map), aa problems, etc.
I re-downloaded the expansion, did a complete file check, and that solved my problems. Worked for a few others too. Any way this is pretty basic advice, which I am sure most of us here know, but it worked for me, and if you didn't think of it already, try it.
If you fixed any other problems, another way, share your solutions. I still know people with unresolved issues.