Files or directories created by PHP when PHP is
running as an Apache module will be owned by the Apache user id. There
is simply no way around that given the current state of Apache. And the
safe-mode restriction correctly restricts you from creating a directory
inside a directory not owned by the same uid as the script. The fact
that it worked before was a security problem which was fixed.
If you want to be able to do something like this, you should consider
using the open_basedir restriction mechanism where all these checks are
done based on the base directory and anything the user does
within/beneath that base directory is ok.
Please read
http://www.php.net/manual/en/features.safe-mode.php and
http://www.php.net/manual/en/configuration.php#ini.open-basedir