Let A be a central arrangement of hyperplanes in Cn defined by the homogeneous polynomial dA. Let Dn be the Weyl algebra of rank n over C and let [Math equation] be the algebra of rational functions on the variety [math equation]. Studying the structure of P as a Dn-module we obtain a sequence of new Dn-modules. These modules allow us to define useful complexes that determine the De Rham cohomology of [math equation]. Finally we compute the Poincaré series of P. © 2006 International Academic Printing Co. Ltd. All rights reserved.