Just get rid of the http:// and you should be all set.
THANKS! Can't believe it was something so simple

Sorry again for the noob post!
I seem to be getting slightly less MH/s than I did with Phoenix 2, although that was with fine tuned paramaters, whears I am passing Diablo no parameters besides my pool. Great MH/s for auto detect settings! Will try and tweak it and see what I can get from Capeverde 7770!
Make sure you're using 12.2. DiabloMiner doesn't autodetect, the default merely happens to work best on GCN. However, no one has tried all options on 7770s yet, -v 2 and -v 4 and -v 2,1 (and 3, and 2,2 and 1,1,1 and 1,1,1,1 and so forth...) probably will be slower for you, but you're welcome to try.
Also, do not use -na, 12.2 fixed this.