This parameter (together with error_cost) is used to limit how many ICMP destination unreachable to send from the host in question. ICMP destination unreachable messages are sent when we can not reach the next hop, while trying to transmit a packet. It will also print some error messages to kernel logs if someone is ignoring our ICMP redirects.
Error_burst controls when destination unreachable messages and error messages will be dropped. The default settings limit warning messages to five every second.