  We prove absolute continuity of the law of the solution, evaluated at fixed
points in time and space, to a parabolic dissipative stochastic PDE on
$L^2(G)$, where $G$ is an open bounded domain in $\mathbb{R}^d$ with smooth
boundary. The equation is driven by a multiplicative Wiener noise and the
nonlinear drift term is the superposition operator associated to a real
function which is assumed to be monotone, locally Lipschitz continuous, and
growing not faster than a polynomial. The proof, which uses arguments of the
Malliavin calculus, crucially relies on the well-posedness theory in the mild
sense for stochastic evolution equations in Banach spaces.
