  A quantum communication architecture is being developed for long-distance,
high-fidelity qubit teleportation. It uses an ultrabright narrowband source of
polarization-entangled photons, plus trapped-atom quantum memories, and it is
compatible with long-distance transmission over standard telecommunication
fiber. This paper reports error models for the preceding teleportation
architecture, and for an extension thereto which enables long-distance
transmission and storage of Greenberger-Horne-Zeilinger states. The use of
quantum error correction or entanglement purification to improve the
performance of these quantum communication architectures is also discussed.
