Case sensitivity is not a bug but problematic for sure. Your account won't get deleted.
Sea surfing should be caused by the use of two windows for browsing simultaneously. It's not cool but well :/
If it happends with a single window, get on #tikiwiki and damian can probably try to see if something's wrong.
RC4 was scheduled to be released tonight but wasn't due to important changes in the installer.
It's expected that we release it tomorrow after some testing.