Site's speed score will effect seo . w3 total cache wordpress plugin creating problem

I have recently setup my website on justhost hosting account.
Website: www.appswhite.com

When I tried to install W3 Total cache it display error on top of the screen on custom permalink structure, not on default permalink.

Error : It appears Minify URL rewriting is not working. If using apache, verify that the server configuration allows .htaccess or if using nginx verify all configuration files are included in the configuration.

and sometimes Page cache URL instead of Minify URL

I strongly need custom permalink structure for my website. Already changed permission for wp-content and uploads folder.
Anything else important to change to use this plugin ?
Anyone to help my ?