Combining CSS files into a single cached one

Yes: put them all in a function, and then enqueue that function at the wp_enqueue_scripts hook. That way, you can define the CSS dynamically (e.g. based on Theme option settings), and let WordPress output it in the document head.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)