Demo Installer Error in Vista

[Software Junkie]

I've just tried to install the Bioshock demo, which I downloaded from Fileplanet yesterday and unlocked at 12:00 (UK).
I'm trying to install it on my Vista 32bit Ultimate OS, but when it gets right to the end I get the following Unhandled Exception error:
"Error Number:0x80040702
Description: Failed to load DLL:GameuxInstallHelper
Setup will now terminate."

[IMG][url=http://imageshack.us][img=http://img263.imageshack.us/img263/7333/bioshockinstallerrorum4.jpg][/IMG]

The setup then quits and erases the gamefiles from my hardrive.
I thought it was because I installed it on a different drive and not the default location, but either way I still get the same error.....
All drivers and OS is up-to-date. Core 2 Duo E6600, 2Gb RAM, 8800GTX, etc
Help!

Update:
The demo installed on my XP partition no problem, so it's not a corrupt installer. I can run the demo no problem from the Vista partition, as the demo is installed on a shared drive between both OS's.
It could be an Installshield issue with Vista......

[Software Junkie]

I see you've posted my original message in this forum...please delete this new thread....thx