WpFastestCacheAdmin not found

I got the following message, when I try to insert an image in a post.

Bezugsstoff-gemustert-Cyclone-Monsoon-Clarke-Clarke.jpg
2. April 2015
30 kB
401 × 400
Bild bearbeiten Unwiderruflich löschen

Fatal error: Class ‘WpFastestCacheAdmin’ not found in /www/htdocs/w00b6cdc/wp-content/plugins/wp-fastest-cache/wpFastestCache.php on line 183

please help

https://wordpress.org/plugins/wp-fastest-cache/