hello bart, after an update i also would suggest this:
1. proceed to the opc's tracking config
2. see if your "adwords plugin" is enabled (green) here:
3. to get it rendered AFTER EACH ORDER, you can enable it for ALL STATUES:
click confirmed, confirmed by shopper, pending (this will make it render always)
4. make sure that the "Enable OPC Tracking ... " is GREEN (enabled within joomla plugins)
5. if you still cannot get it working, let me know and i can check it on your site.
best regards, stan