Try removing the hacks and see if that helps things. It's a good idea to remove your entire downloads folder before installing an ep and make sure it runs already before reintroducing them. Even still, I don't put any hacks back in until I'm sure they're either compatible or updated.
Also, try updating your drivers and see if that helps. Try taking a look through
this post as well. It lists some known issues with Nvidia cards on both Vista and XP (since you didn't specify which you have). It starts about 1/4 of the way down the page.