ROUTINE TO CONVERT A STRING NAMED KP PARAMETER TO A NUMERICAL INDEX :Params: kp_data: in, required, type=structure the data structure (not sure why this is passed, something to check later) base_tag_count: in, required, type=integer the number of base level tags in the data structure first_level_count: in, required, type=integer the number of first level tags in the data structure base_tags: in, required, type=strarr(base_tag_count) the names of the base level tags first_level_tags: in, required, type=strarr(first_level_count) the names of the first level tags.