New post have errors

Whenever I post something the post comes out good but there’s always a message that comes with it. I don’t know what’s going on. I did uninstall wordpress a while ago and yesterday I reinstalled it and this happened.

The error message reads:

Warning: array_key_exists() [function.array-key-exists]: The first argument should be either a string or an integer in /home/animati1/public_html/wp-includes/category-template.php on line 176

Link to site: http://animationnexus.com/