When there's no license found, it's supposed to prompt you for a license. It's skipping this process?
Try manually copying your license file into "c:\Program Files\SlickEdit...beta5\win". After doing this can you start SlickEdit?
If it doesn't run, try a clean config: win\vs -sc <some-new-dir>
I did some quick testing on Windows 8.1 and didn't have any problems.