I just had this problem with the Beta 2 advance zip on my server. It turned out there was a permission problem on my server I guess when files are extract they get 664 permission instead of 644 permission which resulted in the problem.
I was able to login with SSH and run this: chmod -R u=rwX,go=rX ~/public_html/
The problem was resolved without needing to do any further corrections.
Hope this helps someone,
AMDbuilder
☆ A M B ☆