If you try turning on shaders, and toribash sets the option back to 0, your graphics card is not new or powerful enough to run toribash with shaders. Generally, if you have onboard graphics, you can't run shaders.
If you happen to have an awesome graphics card, and you know that for a fact [Nvidia 8 series or higher, or whatever the ATI equivalent is], it may be a driver issue that's causing toribash to think that your card can't handle it. If this is the case, I would suggest updating your graphics drivers to the most recent stable version.