  The Dirichlet problem for a class of stochastic partial differential
equations is studied in Sobolev spaces. The existence and uniqueness result is
proved under certain compatibility conditions that ensure the finiteness of
$L^{p}(\Omega\times(0,T),W^{2,p}(G))$-norms of solutions. The H\"older
continuity of solutions and their derivatives is also obtained by embedding.
