hey amit :wave:
firstly you did not mention what distro you using but looking at your profile then i guess u have redhat 9.
if i m wrong and if by any chance you are using mandrake then try vivek's wonderful page on Cyberoam Client. the process won't work on redhat machine as there is an errno.h issue with demontools. anyways u can read it here
about getting disconnected. have you tried linc? i m using linc on Slackware 9.1 without any problems and if you run it as "linc -d" (debug mode), you will know as to what is happening at time of disconnection.
lastly, about GUI. well i m still to see a GUI client for cyberoam. if you find one, pls do tell me
[EDIT]oops, seems to me someone was posting concurrently