After a smooth install in version 2006102600 of XAMPP + 1.8
Add a new forum post exits apache child with status 128
These things seem OK for me ... try a new download of the code to be sure you aren't missing files.
I can reproduce the first error with a download of HEAD just now. Apache dies with "[notice] Parent: child process exited with status 128 – Restarting" when running course/edit.php. This is the same error as mdl-7382 when trying to post to a forum. Only started happening with me this week, so I haven't been able to test anything to do with HEAD :/.
I still cannot create any courses in 1.8 - but I suspect it's not anything wrong with moodle, and probably a server config problem. This is OK to close for me.