As for mod_security - yes, it is enabled, and I will be investigating further to see if that is indeed the culprit (it does make sense).
Otú ọ dị, nkwenye na-arụ ọrụ ma ọ bụrụ na ha bụ ezigbo (ee, onye nwere ike ịga ma chọpụta ma ihe a na-ekwu bụ eziokwu).