Sorry, I do not know what modem, MB settings, version Kppp, you are using. However, the listing you have givin are correct except for:
b. /etc/chatscript/pap - 'noauth' should be left commented out.
If you are using the newer versions of Kppp, you must first remove all of the pre-set accounts, OK every thing closed. Close out Kppp, re-open Kppp and set your stuff up, then maybe it will find the modem and off you go.