eondesigner

 
@rb_man, I had the same problem and solved it by doing this: 
 
1. open the DA2 launcher.
2. run the DLC installer, it says can't install because DA2 is running or some similar error.
3. leave the error box open and exit the DA2 launcher.
4. press OK in the error box and try the DLC install again and it should work. 
 
good luck