I started with the Corel/debian linux download version. Kppp worked fine. Then I made lots of changes.
I did an "apt-get dist-upgrade" to potato, which went fine. This removed the Corel kde installation so I got the standard kde 1.1.2 debian distribution from kde.org, which also went fine. I noticed the pppconfig/pon/poff feature which comes with debian, so I went thru the configuration and now pon/poff works fine. BUT!!! kppp (which I love and planned to use primarily) is now broken. kppp will dial and connect to the point where the modem returns a "CONNECT" and then the modem hangs up instantly, with no useful diagnostic messages. The same happens whether dialing as root or as me, so file perms are not the problem. I wonder if the configuration files left behind by pppconfig could be interfering with kppp? Any hints much appreciated! P.S.--I also installed xfree86 4.0 in the meantime, which also seems to be working fine. I can't imagine how that would break kppp, though.