.profile doesn't get executed at login

It's strange, I use .profile in my home directory to set environment variables. But it doesn't get executed at login, I have to run it manually every time I login.Can anyone explain this? and how to make it run?thanks for any input.
[255 byte] By [SunLab] at [2007-11-26 10:23:43]
# 1
What shell do you use? 7/M.
mAbrante at 2007-7-7 2:25:11 > top of Java-index,Solaris Operating System,Solaris Essentials - General Technical Questions...
# 2
korn shell, as a echo $SHELL shows.I set in the .profile to use ksh and vi with the following two lines:set -o viBut everytime, I have to type command after login.
SunLab at 2007-7-7 2:25:11 > top of Java-index,Solaris Operating System,Solaris Essentials - General Technical Questions...