I've installed WordPress MU (latest RC1 version) in my ftp space, with php5 and safe_mode=OFF. I've also installed WP Super Cache in mu-plugins directory, following the instructions step-by-step.
However, the plugin's configuration page returns me the error:
Warning! PHP safe mode enabled!
You may experience problems running this plugin because SAFE MODE is enabled. Your server is set up to check the owner of PHP scripts before allowing them to read and write files.
You or an administrator may be able to make it work by changing the group owner of the plugin scripts to match that of the web server user. The group owner of the wp-content/cache/ directory must also be changed. See the safe mode manual page for further details.
What should I do? :(
PS: sorry for my bad English, I'm Italian... :P