Supporter Error Message

Hello,

if someone create a blog then comes the message:

Warning: Missing argument 3 for activate_plugins(), called in /.../wp-content/mu-plugins/supporter-plugins.php on line 169 and defined in /.../wp-admin/includes/plugin.php on line 570

First the plugin menu in settings was deactivated. So I activated the plugin because of this problem. But the error message comes.

Can you say what is wrong?