I am having this error just recently. It works fine 2 weeks ago and the error just showed up 2 days ago.
Warning: array_flip() [function.array-flip]: Can only flip STRING and INTEGER values! in /xxxxx/xxxxxxx/batangastoday.com/wp-content/plugins/capa/capa.php on line 884.
I have no choice but to deactivate the plugin. The error shows on every permalink pages. Anyone encountered the same? How did you fix it?