[t3hNox]

Check "core program".
You use iParamID incorrectly. iParamID returns the total amount of parameters passed to the native. For example, for bkf_setFrags you should pass 3 parameters and thus in native handle you should check whether iParamID is 3 (to avoid possibility that too many or not enough parameters are provided) and get the first parameter by using get_param(1) (id), get_param(2) (level), get_param(3, szReason, charsmax(szReason)) (reason). I'm also not sure if you can specify "a default" value for reasons.