@ait1
I personally have not installed this plugin as it is a 3rd party plugin (I would not fully trust 3rd party anything).
It would be in your best interest to contact the developer of the plugin for further assistance. Since this is not a core plugin that the osTicket Team developed we will not be able to provide assistance.
Also, v1.8 is extremely old, outdated, and vulnerable to many serious security vulnerabilities. You should upgrade to v1.15.4 ASAP to take advantage of the latest features, bug fixes, and security patches. You can review the Upgrade Documentation here.
Cheers.