The same thing is happening to me. Haven't played in some time and I come back to this.
As far as I can tell, all my clubs are my own. I don't even recall renting any clubs as I have not played in a few years. It was working fine when I stopped then. I believe it says you need a bag to play although I have no idea why this is necessary, except to squeeze more money out of us. So I spent the 5 bucks or whatever to get a bag, and still get the error.
So I am out 5 bucks and looking at posts on here that say this has been happening for years here?? And still not fixed?
My guess is that the only solution is to buy new clubs and equip them. However I am not going to spend that money, when I have no guarantee it will work, nor should I have to.
Looks like I won't be playing anytime soon.
Oh and keep sending those emails asking me to refer people to this game. At least that part of it still works well.