I have a similar error.
Plugin could not be activated because it triggered a fatal error.
PressBackup: Please change the value of prefix, on config/config.php
Warning: Please change the value of prefix, on config/config.php in <snip>htdocs/blog/wp-content/plugins/pressbackup/.core/w2pf_init.php on line 54
Fatal error: Class name must be a valid object or a string in <snip>htdocs/blog/wp-content/plugins/pressbackup/main.php on line 15
I have full 777 permission for the pressbackup directory in plugins.
I do have the blog in a subfolder and would this make a difference ?
What should I enter in the prefix field ?
Thanks