ORDER 1 M(B)(3) CORRECTIONS TO B-]X(C)L(NU)OVER-BAR DECAY AND THEIR IMPLICATION FOR THE MEASUREMENT OF (LAMBDA)OVER-BAR AND LAMBDA(1)/

We compute the order 1/m(b)(3) nonperturbative contributions to the in clusive differential B-->X(c)l (v) over bar decay rate. They are param etrized by the expectation values of two local and four nonlocal dimen sion-six operators. We use our results to estimate part of the theoret ical uncertainties in the extraction of matrix elements <(Lambda)over bar> and lambda(1) from the lepton spectrum in the inclusive semilepto nic B decay and find them to be very large. We also compute the 1/m(b) (3) corrections to the moments of the hadronic invariant mass spectrum in this decay, and combine them with the extracted values of <(Lambda )over bar> and lambda(1) to put an upper bound on the branching fracti on B(B-->D*l (v) over bar.