I have a weird issue with a custom made child theme for the default Twentyten theme (shipped with WordPress 3.0).
After I activate the child theme (without any warning) every "Publish" or "Save changes" action results in a blank page. At some times even logging in to the admin section results in a blank page too.
This problem was solved after deleting the functions.php file I had included in my theme. First I thought I messed up something there, but even an empty functions.php file causes the same issue.
I'm a bit clueless, because I used the same child theme on another wordpress setup without any problems. Only thing different in this case is that we setup wordpress as an MU platform.
Anyone any thoughts on what could cause this issue?
Problem is similar to: http://wordpress.org/support/topic/413853 but my server settings (PHP version, ...) shouldn't be any issue.