  Using 13.53/fb of CLEO data, we have measured the ratios of the branching
fractions R+(e) = BF(D+ --> K*0bar e+ nu_e) / BF(D+ --> K- pi+ pi+), R+(mu) =
BF(D+ --> K*0bar mu+ nu_mu) / BF(D+ --> K- pi+ pi+) and the combined branching
fraction ratio R+(l) = BF(D+ --> K*0bar l+ nu_l) / BF(D+ --> K- pi+ pi+). We
find R+(e) = 0.74 +- 0.04 +- 0.05, R+(mu) = 0.72 +- 0.10 +- 0.06 and R+(l) =
0.74 +- 0.04 +- 0.05, where the first and second errors are statistical and
systematic respectively. The known branching fraction BF(D+ --> K- pi+ pi+)
leads to: BF(D+ --> K*0bar e+ nu_e) = (6.7 +- 0.4 +- 0.5 +- 0.4)%, BF(D+ -->
K*0bar mu+ \nu_mu) = (6.5 +- 0.9 +- 0.5 +- 0.4)% and BF(D+ --> K*0bar l+ nu_l)
= (6.7 +- 0.4 +- 0.5 +- 0.4)%, where the third error is due to the uncertainty
in BF(D+ --> K- pi+ pi+).
