Okay, your iBook came with Jaguar v. 10.2.1, what you want is to update it to 10.2.3 to be current.
You should have no problems updating the system to 10.2.2 by running the file you downloaded.
When you're done, open the System Preferences and click on the Software Update utility. This will find the 10.2.3 updater on Apple's Software site, it will download it for you, install it for you...and you're up-to-date.
[ 02-06-2003, 12:35 AM: Message edited by: kps ]