Please read this carefulll before you use KSudo
The load function of KSudo supposes that every line in the file, except the empty ones and the ones starting with a '#', contain either an alias, a default or a user specification. So if you want to load your current /etc/sudoers file please ensure that there are no aliases, defaults or user permissions that use more than one line. Furthermore the load function asumes, that every permission line only contains one command or one command-alias.
Furthermore KSudo supposes that your sudoers file is located at /etc/sudoers. A configuration dialog for this will come with one of the next versions.