Fatal Error when trying to activate

I have used this plugin before and then uninstalled when not using it.

Unfortunately, today I got an error message when I tried to activate it.

Any suggestions?

Plugin could not be activated because it triggered a fatal error.
Parse error: syntax error, unexpected token “::”, expecting “(” in /wp-content/plugins/search-regex/models/search.php on line 322

The page I need help with: [log in to see the link]