Hi Tim,
It is a notice and you can ignore it. However we will remove that notice in next release.
Regarding the js error, can you please deactivate other plugin and see if it still exists ? There might be some conflict with other plugin. If this works, you can activate one by one any see which plugin is making the issue. We will try the fixes as per it.
Or if you wish, you can send us your wp-admin details using our form from here https://dineshkarki.com.np/contact. I will check and try to fix it.
Thanks