I instaled DDO in another machine, it has Win7. I execute dndlauncher.exe with Administrator access... it loads a little and it doesn't open nothing. I added to my firewall exceptions list, and nothing. I don't know why this happens.
Here I got some images, but it's easy to imagine... launcher doesn't do nothing. Just like that.
http://imageshack.us/g/857/foto1l.png/
My laptop is a Compaq cq41-226LA and I tried with both clients (Hi-res and Standart-res)