I would recommend viewing the e-presentation even if your school does host presentations. This way, you can view the presentation and apply as soon as its available (some schools don't have presentations until months after the application becomes available, which can result in limited opportunities for roles, acceptance, etc; the longer you wait to apply, the less likelihood there is for getting smaller roles). You can always go to your school's presentation later; this is a great way to get questions answered if you have them, or to meet people from your school who might be going.
You're not out of luck at all. It's definitely still doable. Your school doesn't have to support it for Disney to let you go; it just might be harder to get all your school stuff taken care of. It might be harder to get credit, as others have said, but you can usually work something out (internship credit, independent study, online courses, courses at WDW, summer courses, etc. Lots of options exist). You might run into issues with housing and course registration for the following semester if your school doesn't have a strong internship policy/history. If your school is being really, really difficult to work with or it's just not working out, you can always wait and apply for the semester after you graduate. For example, if you graduate in Spring 2011, apply for Fall 2011. You only have to be taking courses when you apply; it's fine if you graduate before you go down. If your goal is to work for Disney long-term, this might offer you more flexibility to extend your CP, go part/full-time, or apply for professional internships, since you won't have to worry about dealing with your school any more.