Users don't sync - Unable to access "admin.php?page=user-sync"

Hi team!

I've just installed User Sync. I'm running WP Multisite 3.5.1, no BPress. My network's comprised of 5 sites.

I've set up the master and slaves sync sites, and when I synchronize I have no error messages, but the users in the master site don't show up in the slaves ones.

I also have no access to "", getting a "You do not have sufficient permissions to access this page." message.

You can access the log files here "" and here "".

Please, Any advice? Thank you!