When I am within my admin panel, under Posts > Categories, I am unable to 'create/add' any categories. The only category that is listed is 'Uncategorized', the default category. When I attempt to create a new category, I receive an error "An error has occurred. Please reload the page and try again."... which is interesting because when I check my database, the category (in which I had just tried to create) was created, and shows within the wp_terms table (with a term_id, name, and slug). However, my newly created category does not show up in my WordPress admin, and therefore I am unable to assign it to any of my posts.
I have been searching and wrestling with this issue for about 4 days now, with no success, and the only information that I could gather was that this issue is very prevalent, across many version of WordPress, and that no one (above WordPress 3.0) has successfully found a solution for it. Frankly, I am very surprised to see that this issue has not been corrected yet. Either way, I am attempting to seek help via this forum, and would appreciate any assistance in regards to this matter. I am running WordPress 3.5.1 (locally), through XAMPP 1.8.1, Apache 2.4.3, PHP 5.4.7, & MySQL 5.5.27.