Rare bug in Dashboard, notice: undefined index

Rare bug in dashoard.

Ik hheb iets gedaan maar weet niet exact wat. Resultaat is dat ik nu deze balk bovenaan mijn dashboard heb staan (lees hieronder) en op de homepage
notice: undefined index (met een tekst erachter) heb staan. Heeft iemand enig idee hoe je dit kan oplossen.

Deprecated: Assigning the return value of new by reference is deprecated in /customers/9/d/d/mijndomein.com/httpd.www/mijndomein/wp-content/themes/razzo/option-tree/includes/ot-meta-box-api.php on line 279 Notice: has_cap was called with an argument that is deprecated since version 2.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /customers/9/d/d/mijndomein.com/httpd.www/mijndomein/wp-includes/functions.php on line 3318 Warning: Cannot modify header information – headers already sent by (output started at �5,�!L16:279) in /customers/9/d/d/mijndomijn.com/httpd.www/mijndomein/wp-includes/option.php on line 750 Warning: Cannot modify header information – headers already sent by (output started at �5,�!L16:279) in /customers/9/d/d/mijndomein.com/httpd.www/mijndomein/wp-includes/option.php on line 751