  We derive the scalar potential of the effective theory of type
  IIB orientifold with 3-form fluxes turned on in presence of non abelian brane
coordinates. N=4 supergravity predicts a positive semidefinite potential with
vanishing cosmological constant in the vacuum of commuting coordinates, with a
classical moduli space given by three radial moduli and three RR scalars which
complete three copies of the coset (U(1,1+n)/U(1)\otimes U(1+n)), together with
6n D3-branes coordinates, n being the rank of the gauge group G. Implications
for the super Higgs mechanism are also discussed.
