A couple of minor points:

This isn't a Perl related question so you should have an 'OT' (off topic) in the subject line.

Please have a look at Writeup Formatting Tips for info on formatting your post so it is more readable.

Firstly, try putting 'set -o emacs' in ~/.kshrc, it may make a difference
Secondly, you can set the default editor by 'export EDITOR=/path/to/favorite/editor'.
Lastly, why ksh? ksh under Linux is the pdksh (public domain ksh) and does not contain the entire feature set of 'standard' ksh. Does bash or sh not meet your needs?

Also remember that if you update your dot files (.kshrc, .profile, etc) you'll need to source the modified files (. ./.kshrc, . ./.profile) or logout and login again.

CC