Some people are currently having problems on windows 8. I know it can be tempting, but usually it's best not to upgrade operating systems the day they're released since new problems often come up once a lot more people try them with a lot of different software.
Since you've already done it though, I'd say download the demo and see if it works for you. If not, hopefully a fix isn't far off, but since I don't know what the problem is exactly, I don't know how hard it is to fix or who needs to fix it. I saw a post from someone else about some kind of windows 7 compatibility mode I think in the "Pro" version of windows 8, and that seemed to help for them.
If the demo works for you though, then you should be fine because it's the same program, just with a few features (like exporting audio and opening songs) disabled. :)