I'm having exactly the same problem. Guests were in my house in Dublin for five nights, but no payment received from Airbnb so far. From what I've seen on the net and in these forums, this seems to be a common problem. I wasn't aware of this before I became part of the Airbnb community and I may have thought twice about it had I known !!
Airbnb are not adhering to their side of the agreement amongst guest, host and Airbnb. I've been on to them several times by email and phone calls. I have been given generic explanations about what the cause might be, but the problem still persists. Very disappointing on my side as I've adhered to all the Airbnb standards.
I have further bookings in the pipeline and am concerened that I'll face a similar problem. I don't want to cancel these bookings as the fault isn't with the guests, but I feel that Airbnb are backing me into a corner.
Very disappointing and unsatisfactory !!!