Pepsai / Steam Automatic Group Invite

I'm using the version 2.0.3

I've setupped the customurl but when i start the file, appear this:
The error

Errore di run-time di Microsoft JScript

Please install a .user.js engine for your browser first. This is usually an IE message so you might also need a different browser unless you have a newer Microsoft Edge version. Userscripts only run in the browser and not in JScript from Active Scripting.

See Userscript Beginners HOWTO for browser support.

Thanks and closing.