Hi Sandy;
Based on the error message ("Fatal error: Cannot redeclare class Minify_CSS_Compressor in /home4/ftworld/public_html/sala-fw/wp-content/themes/website/drone/ext/minify/css.php on line 21") you have a theme that tries to do CSS minification itself. That means you'll have to choose to use that one, or (if you can disable CSS minimization in your theme) Autoptimize's CSS minification.
As far as javascript is concerned; you'll have to exclude certain scripts from being Autoptimized. To do that you'll have to dive in the HTML, checking which javascript is loaded and in the JavaScript error console to see which scripts are complaining and play around with the exclude options until it works.
Hope this helps,
frank