Here is an example Embedded Event Manager applet I built for someone that wanted to watch an interface's CRC errors:
http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=WAN%2C%20Routing%20and%20Switching&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.1ddeb96c/1#selected_message
The idea is similar for what you want to do. Something like this should work:
event manager applet interface_errors_shutdown
event interface parameter input_errors entry-op ge entry-val 6000 entry-val-is-increment true name "FastEthernet0/0"
action 1.0 cli command "enable"
action 2.0 cli command "config t"
action 3.0 cli command "int fa0/0"
action 4.0 cli command "shut"
action 5.0 cli command "end"
action 6.0 syslog msg "Shutting down FastEthernet0/0 as input errors in the last minute were $_interface_value"
This will check for an error rate of 100 per second. This applet will only work with IOS 12.3(14)T or higher (or 12.2(18)SXF5 or higher on 6500).
