Single-loop amplitudes with three or four external particles are constructed in the supersymmetric dual theory. The three-particle loops vanish, signifying the absence of coupling constant renormalization. The four-particle planar-loop amplitude has a divergence that can be absorbed into a renormalization of α', the Regge slope, since it is proportional to the derivative of the tree amplitude with respect to α'. Furthermore, we demonstrate that this divergence can be expressed as the emission from a tree of a zero-mass closed-string scalar state at zero momentum. There is also a divergence in the non-planar loop that couples one external SU(n) singlet [the states of the model are SU(n) singlet and adjoint representations] to three other particles. This divergence can be interpreted as a wave-function renormalization for external singlets. The non-planar loop with s-channel SU(n) singlet quantum numbers is shown to contain poles corresponding to the states of the closed-string sector of the theory (which includes the massless states of simple d = 10 supergravity).