A method for providing reliability in a multicasting communications system having a communications path between a content server on a server side of the communications system and first and second user systems on a client side of the communications system via a server system on the server side of the communications system, the communications path comprising a shared forward link over which bandwidth resources are shared, the method comprising: observing, at the server system, a response to a first request for an object from the first user system ; multicasting the object over the communications path to the first user system and the second user system, which enables the object to be placed on the second user system in anticipation that the object will later be requested by the second user system; receiving, at the server system, a reliability message from the first user system, the reliability message identifying a block of data from the object in which an error or omission was identified; communicating a first object repair message to the first user system; characterized in that the method further comprises: receiving, at the server system, a second request for the object from the second user system after communicating the first object repair message to the first user system; and communicating a second object repair message to the second user system in response to the second request for the object from the second user system, the first object repair message and the second object repair message each individually comprising repair information for the block of data. observing, at the server system, a response to a first request for an object from the first user system ; multicasting the object over the communications path to the first user system and the second user system, which enables the object to be placed on the second user system in anticipation that the object will later be requested by the second user system; receiving, at the server system, a reliability message from the first user system, the reliability message identifying a block of data from the object in which an error or omission was identified; communicating a first object repair message to the first user system; characterized in that the method further comprises: receiving, at the server system, a second request for the object from the second user system after communicating the first object repair message to the first user system; and communicating a second object repair message to the second user system in response to the second request for the object from the second user system, the first object repair message and the second object repair message each individually comprising repair information for the block of data. receiving, at the server system, a second request for the object from the second user system after communicating the first object repair message to the first user system; and communicating a second object repair message to the second user system in response to the second request for the object from the second user system, the first object repair message and the second object repair message each individually comprising repair information for the block of data. <EOS>