Which is something similar problem mentioned in http://wordpress.org/support/topic/11-is-broken?replies=27
After doing a review on the minify generated code, we found that the HTTP/1.0 400 Bad Request is happening because of an extra / after wp-content/plugins/aio-shortcodes/ it may be generating by the aio-shortcodes plugin.
1) Please try deactivating the aio-shortcode plugin
2) try deactivating the wp minify plugin
Please let us know the status of this problem after trying the above mentioned solutions.