Ambicon WL300N-AR Router AP And Broadcast

They currently have three Ambicon WL300N-ARs in their network. They are set up as AP and everything has been running fine till we tried to put a security DVR/camera behind each router. The first one worked without any issues but once we connected the second DVR to the network became unusable, very slow. Someone told the IT guy that it was probably a broadcast storm. I don't know anything about the ambicon routers, but if the wireless is setup as a AP would it forward broadcast? I was under the impression that routers did not forward broadcast. or by setting it up as a AP it no longer performs as a router? The three Ambicons are connected to a unmanaged fiber switch, I asked for a make and model but he didn't know. Also connected to the fiber switch is another unmanaged netgear switch.