Need help playing this game on my laptop

[Dukelord]

Hi folks.Pls I need help playing a game on my laptop...
First of has anyone ever heard of a game called Penumbra?
It's an open-source game developed by a bunch of 4 Swedish college students...
It's a project testing new dynamics of physics in video games...
Penumbra is a horror game which according to reviews comes with great graphics and good gameplay...
The full game can be downloaded for free on the internet.....gamershell.com
My laptop specs is as listed below;

HP Pavillion dv5157eu
AMD Turion 64 1.8GHz
1GB DDR RAM
100GB HDD
128MB ATI Mobility Radeon Xpress 200M(Not shared)...

Now then,to the problem...
I downloaded Penumbra,installed it,there's even an update,I downloaded that and updated Penumbra,when I click on the .exe file,the game starts on,comes up with the menu,I click on new game...there's an intro to the game which is just a bunch of art slides with a voice giving the story of the game,after that,a loading screen comes up and then bam!!!!!!
I get an error message...
I've tried everything possible,I've been to the option menu and tried tweaking the graphics setting...even to the lowest possible,but still no luck...I just installed the latest ATI Catalyst drivers for my graphic chipset,but still no luck with Penumbra.Someone who can help should pls do.Thanks folks