Alexia

This is a configuration issue with your PHP installation.

Edit your php.ini to have error_reporting set to E_ALL & ~E_DEPRECATED & ~E_NOTICE.
Example:

; Common Values:
;   E_ALL & ~E_NOTICE  (Show all errors, except for notices and coding standards warnings.)
;   E_ALL & ~E_NOTICE | E_STRICT  (Show all errors, except for notices)
;   E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR  (Show only errors)
;   E_ALL | E_STRICT  (Show all errors, warnings and notices including coding standards.)
; Default Value: E_ALL & ~E_NOTICE
; Development Value: E_ALL | E_STRICT
; Production Value: E_ALL & ~E_DEPRECATED
; http://php.net/error-reporting
error_reporting = E_ALL & ~E_DEPRECATED & ~E_NOTICE

Read the install-license.html file included.