Hi there! Bringing this up as this problem seems to (still!) exist.
I had IP 4,2 installed, and now i decided to upgrade to version 5. So i downloaded the public version (5,1) from the site, and it gives this very error.
Is there any solution? Installing via Impulse does not seem to help as i don't see the free/public IP there for download.
/7 Ultimate SP1 x64/
EDIT:
So, after some more research i've managed to fix this. The problem lies in the installer that Stardock uses. On the forums of the installer there are several posts with this error, and a fix for that is just to rename, move or delete IconPackager.exe from the temp folder listed on the error window. Then the installation continues 