Hello Amit, and Greetings!
I use a dial up modem, so maybe I can help.
Do you know what modem settings your modem uses (were you able to set it up using another LINUX distro, did wvdialconf give you settings?)
This first happened to me a few years back with when switching to a new modem using Mepis.
Recently, though, I had kppp crash happen often with KDE3 desktop, so the version shouldn't really matter. I'm not sure what really caused it, but it was after I had already installed Pardus with one modem (Best Data using serial to USB adapter cable), which died from a thunderstorm. I then switched to a US Robotics using the same cable and set it up as new modem, which is when I started getting the crashes. I noticed that with the new modem set up, in the tab, modem commands, the fields were all blank, and I had to manually fill them in. I had written the default fields down previously when using a live disk. But, I shouldn't have had to manually fill them in.
I am now using a new modem and did a reinstall of Pardus 2008.1 and all is well, as the default fields were there, and I basically used the default settings. My ISP requires PAP authentication, so I added PAP to the kppp selection of pap/chap. My modem uses a usb cable and I'd already read up about this particular modem, that it uses device: ttyACM0. My previous modems used ttyUSB0 since they used a converter cable. Lock file is ticked. I set modem speed to 57600, otherwise I had problems getting connected if I used anything higher.
In case your modem commands field is blank, here are the defaults:
50, ATZ, Post init: 50, 70, OK, ATX3, ATDT, CONNECT, BUSY, NO CARRIER, NO DIALTONE, +++ATM, OK, ATA, RING CONNECT DIGITAL LINE DETECTED, +++, OK, 50, M0L0, M1L1, MLL3
Some of the newer USB modems are difficult to set up in kppp. What modem are you using?
It would be nice to know how compile wvdial in Pardus, or that one day they will add it to the distro since it automatically detects the modem and tells you what module it uses. wvdial detects my modem Baud/bps speed of 486000, which is much too fast. I had to change it in wvdial.conf file to 57600.