Lawrence, the most important thing to do when installing any new program is to make sure you have ALL other running programs, except EXPLORER (your Windows program) and SYSTRAY closed down. You do this by pressing CTRL-ALT-DELETE, highlighting any programs listed, one at a time (except the above two),then clicking on END TASK. Once that is done, then proceed to do normal Windows install: START|SETTINGS|CONTROL PANEL|ADD/REMOVE PROGRAMS and browsing to where you have the download saved. If you have a partial install left over from your previous attempt, make sure that is deleted first. And it goes without saying, make sure you have backups of your current ".paf" files.
If you still have problems with your "ikernel", you may need to re-install the ikernel.exe file again. You can do this by going to this site: http://support.installshield.com/http://support.installshield.com/
In the section in the middle of the front page, headed "FIND A SOLUTION" click on "NEW! KNOWLEDGE BASE" On the next page - "KNOWLEDGE BASE", type: Q105097 in "ARTICLE ID" and click SEARCH On the next page, click on the document link: Q105097 - INFO: Install the Latest Version of Ikernel.exeDec 13,2000 You will then see the install box open in a new window.
But the first procedure should see you well on the way to having PAF 5 up and running, so this (the last suggestion) is just an "emergency" procedure, in case you need it :-)