Excitation of potential surface waves by a nonrelativistic electron beam traveling in a vacuum space near the boundary of a layered superconductor is studied theoretically. Dispersion relations for surface waves at an arbitrary angle between superconductor layers and interface are obtained. Allowance is made for an arbitrary direction of wave propagation in the interfacial plane. Increments of kinetic and hydrodynamic instabilities are found. It is shown that absolute instability may occur.