Fullscreen not running.

[Sexbad]

My monitor supports up to 1680*1050 and I use that most of the time, but when I review games, as I intend to do with Amnesia, I go to a resolution such as 1280*800. I tried to change from the former to the latter and it crashed. hpl.log coming right up.

EDIT: Disregard this. It was when I tried to turn on Vsync! Just changing the resolution was fine, but it crashed when I toggled the Vsync setting. Now it crashes at the start when Vsync is turned on. It may have had nothing at all to do with fullscreen in the first place.

hpl.log:

Spoiler below!

-------- THE HPL ENGINE LOG ------------
Engine build ID 20100818114615

Creating Engine Modules
--------------------------------------------------------
Creating graphics module
Creating system module
Creating resource module
Creating input module
Creating sound module
Creating physics module
Creating ai module
Creating gui module
Creating generate module
Creating haptic module
Creating scene module
--------------------------------------------------------

Initializing Resources Module
--------------------------------------------------------
Creating loader handlers
Creating resource managers
Adding loaders to handlers
--------------------------------------------------------

Initializing Graphics Module
--------------------------------------------------------
Setting video mode: 1280 x 800 - 32 bpp
Init Glew...OK
Setting up OpenGL
Vendor: ATI Technologies Inc.
Renderer: ATI Radeon HD 4800 Series
Version: 3.3.10151 Compatibility Profile Context
Max texture image units: 16
Max texture coord units: 16
Max user clip planes: 8
Two sided stencil: 1
Vertex Buffer Object: 1
Anisotropic filtering: 1
Max Anisotropic degree: 16
Multisampling: 1
Texture compression: 1
Texture compression S3TC: 1
Auto generate MipMaps: 1
Render to texture: 1
Max draw buffers: 8
Max color render targets: 8
Packed depth-stencil: 1
Texture float: 1
GLSL Version: 3.30
ShaderModel 2: 1
ShaderModel 3: 1
ShaderModel 4: 1
OGL ATIFragmentShader: 1
Adding engine materials
Initializing DevIL
Vendor String: Abysmal Software
Version String: Developer's Image Library (DevIL) 1.6.8pre Aug 12 2006
Version Number: 168
Adding engine post effects
--------------------------------------------------------

Initializing Sound Module
--------------------------------------------------------
Initializing OpenAL
Available OpenAL devices:
0. Generic Software on Speakers (2- Shure Digital )(OpenAL default)
1. Generic Software on Digital Audio (S/PDIF) (High Definition Audio Device)
Trying to open device 'Generic Software on Speakers (2- Shure Digital )'... Success!
Number of mono sources: 32
Streaming setup: 4 Buffers x 262144 bytes each
--------------------------------------------------------

Initializing Game Module
--------------------------------------------------------
Adding engine updates
Initializing script functions
--------------------------------------------------------

User Initialization
--------------------------------------------------------
- DEMO VERSION -
--------------------------------------------------------

Game Running
--------------------------------------------------------