Help us help you on this one, you didn't supply a lot of information...
- Confirm that you are using the Titanium client to play. Funky stuff happens without it.
- Tell us what weapons you are using, being sure to specify primary and offhand
- Tell us your level, strength, attack rating
- Post a log of you using the discipline (can surround in code tags)
I should mention, I've seen some funny posts from rogues saying their damage output is wrong and something is off. Turns out they had ragebringer in offhand or had accidentally looted an inventory item during corpse recovery and were actually backstabbing with an FS dagger!