If you switch to a different shell, such as ksh, from the standard shell, bash, you should be prepared to adapt bash shell scripts to ksh scripts. Depending on which version of ksh you are using, the 'dot' command should work in ksh (the source command comes from csh). However, the commands in the setvars.sh scripts may not mean the same things to bash and ksh, so again you may need to make changes.
An alternative is to start a bash session, 'source' or 'dot' the Intel setvars.sh script, and then run ksh from the bash command prompt.
One wonders what it is that ksh provides to you that justifies this extra trouble that you have to go through.