Does anyone have some idea what is my system missing that prevents it from running the GOG release of Ultima Underworld?

When I try to start the game I get the following error:
"You can't open the application Ultima Underworld 1.app because it is not supported on this type of Mac."

System Details
2006 MacBook Pro 17" version 1,2
OS X 10.6.8 (Snow Leopard)
Intel Core Duo 2.16 GHz
2GB RAM
ATI Radeon X1600 256MB VRAM

Minimum system requirements for Ultima Underworld as listed on GOG:

Mac: OS X 10.6.8 or later
Processor: Intel Core Duo 2GHz+
Memory: 1GB of RAM
Graphics: 64MB

Solution Update:
The .app contains another version of the .app file inside its package and it seems to work fine without any modifications or additional software.

All I did was:
1. Right click on the .app file
2. Select the Show Package Content option
3. Run the App found inside the Contents > Resources > game folder

I did not have the time to play the game yet to find out what the differences between the App versions are or if there are any problems, but will update this post if I do later on.