They shouldn't be disabled in the first place. They should work the same.
Try this test:
Create a simple brand new test file in FMP12. Do you have the same issues? If it works fine there's an issue with your converted file. Try recovering it. If it has the same problem, the issue likely lies with your computer or the install of FileMaker 12--you may want to call tech support so they can walk you through typical fixes. (It's been my experience that they don't charge you for installation problems.)