Hi there!
First, remember:
- 0 = The first custom parameter
- 1 = the second custom parameter
and so on.
Now, it does not seem that my plugin is the problem there. All the errors on the console are pointing to Visustella plugins. As so, I cant say anything about that. The only thing I can say for sure that the "cannot read property "cparam" of undefined" means that it is not finding an actor to do whathever you want to do with the cparam. So I guess maybe there is something wrong with your event system that is not properly switching the actors. Don't know about that, you have to find out.
But also, try the easy way first. Just put an event with just one plugin command to change a single actor custom parameter. Just so you can confirm that the problem is the Custom Parameter plugin or not.
As for your event, nothing seems wrong to me. But maybe I can help you make it simple. Since you are changing only the party leader custom parameter, you can use the plugin command this way below. If you set Battler Type to party it will look for the actors in your party, by their index(position) number. As so, just put 0 on the Battler/index as it will always point out to the party leader.