Re: 1.0 b2 on WP MU 2.7 so far…
If you are getting blank screens you need to check your logs to see the errors. The likely cause is that you are using functions that no longer exist.
If you can find out which functions are in question, it will be quite easy to fix. This is the problem with creating new themes before the default theme is final unfortunately. Once the theme is 1.0, you won’t run into these problems.