Problem 1: this is normal, middle name is a core field, to enable this you need to set in Easy Profile options the parameter "Name Style" to "First Name,Middle Name,Last Name"
Problem 2: This is a PHP warning (no error), these notices are logged by server and not displayed. In your server you have a bad configuration, you need to set in php.ini this "display_errors = Off". If you do not know what it is trying to contact your system administrator.
Anyway in next release we will try to remove this warning.
