Try reinstall toribash, if this dont helps you problably got to low pc. But i dont know if ur pc would be to low u would still have shadders but everything black..:/
I don't recall ever getting an error message when I tried to run shaders (even though I can't), but, then again, I haven't played on the newer versions.
Best I can tell you is the same things as the guys above: your PC specs are too low to run them, which means you have two options: use fake shaders or upgrade your computer.