Update Manager Installshield requires, from some folks, a file called "isus.msi". If it can't find this file - for whatever reason - it requests that a mystical, magical CD you have never heard of be inserted into your CD/DVD drive. The message accompanying this is usually cryptic.
"What disk?!" you scream at the uncaring monitor. Now comes the test of your webfu, frantically searching the interwebz in a quest to find The Solution.
But, before you download a questionable piece of "helpful" software, or the supposed file, or edit your register, or any other wacky, dangerous, or dubious fix: get the first installation disk of CorelDRAW X3 collecting dust in your stack/box/spindle/whatever and put it in the CD/DVD drive. You can find isus.msi in the directory :\CGS13. You'll have to search the disk if it's not in that spot. Then: just [BROWSE] your way there and click [YES].
And that's how the day was spent. Hope this helps.