ScriptUO is just a code editor and doesn't run stuff. Any changes you make with it you'll need to save and open with EUO.
I play a bunch of other OSI shards. There is a small number of people who can never get their setup working for some reason. Has to do with their OS, video card, video card settings, etc. Sometimes they just never figure it out. Did you go though the check-list on the first post?
I don't know anyone who's tried this with Windows 8. I generally run this with WinXP and Win7