I’ve yet to see this issue resolved to anybody’s satisfaction, regardless of what form it takes. I too have been experiencing this – I’ve now run into my 2nd plugin that throws this error upon trying to administer it. No, it’s not in the db twice. Are there any other suggestions besides check the version of php??
I’ve spent an inordinate amount of time trying to track the problem. I’ve ensured all calls are “_once” and found only 2 places the plugin is being referred to – one is in the header itself where the hyperlink calls the plugin so you can administer it, and then the screen that should come up when you click the hyperlink. Surely the header isn’t declaring the function that the plugin admin screen is then trying to (re)declare.
