hello gail, i found the problem. the OPC's javascript is overwritten by one of your plugins:
plg_system_vmcraftyclicks_vm_class
when i disabled the plugin, opc's scripts got loaded properly.
let me know how to move from here and what is the purpose of this plugin. i think it also can get disabled within the plugin config itself, once you rename the country field to some non-existent value.
i used this to find out:
best regards, stan