The rules state:
"A Dawnflower dervish gains the Dervish Dance feat as a bonus feat.
This ability replaces bardic knowledge."
Currently, the Bard properly loses Bardic Knowledge but fails to gain Dervish Dance as a bonus feat. (It doesn't specifically mention prereqs for the bonus feat, but as it replaces a core class ability I believe they're overlooked.)
Section 15: Copyright Notice - Pathfinder Campaign Setting: Inner Sea Magic
Pathfinder Campaign Setting: Inner Sea Magic. © 2011, Paizo Publishing, LLC; Authors: Jesse Benner, Jason Nelson, Sean K Reynolds, Owen K.C. Stephens, Russ Taylor.
This is not coded up in our repo. Nothing to implement or fix.
The confusion here is between the "Dawnflower Dervish" bard archetype from Inner Sea Magic, which we don't have in our repository (yet!), and the "Dervish Dancer" bard archetype from "Ultimate Combat". These are similar, but different concepts. Loading "Ultimate Combat" will not give you the Dawnflower Dervish.
A rudimentary data set for "Pathfinder Campaign Setting: Inner Sea Magic" containing the Dawnflower Dervish bard archetype and the Tattooed Sorcerer sorcerer archetype has been added to the notfordistribution folder in the repository, Subversion revision 19684.
I apologize for my confusion! And thanks for being awesome about it.
Please fee free to point out any problems with the archetype if you try to use it. One issue, as far as I know, is currently not being figured in, that is the effect the Bloodline Tattoo ability.