Kppp modem lock file

Thanks to Jiva and The Wolf got ppp working. Now it is Kppp
that is giving problems. Am using RedHat 6.2 on a Pentium 450Mh,
128 MB RAM. While in KDE and select Kppp from the popup
menu all that is displayed is a box asking for the root password. The
box disappears and nothing happens so I guess that it is a RedHat
problem. From the CLI I type in /usr/sbin/kppp and get the box
for initiating Kppp and then select connect. All that happens is a box
the says "Sorry, can't create modem lock file." and thetas is it. How
is the "modem lock file" created?
Clay Stapleton