I ran into this problem with the 17.1.0 version of the driver for the AC 7260 dual-band mini-PCI Express card on my Dell XPS 15 L521x laptop. Basically the driver fails when waking from the sleep state and cannot connect again until you disable and re-enable the card. As far as I can tell after working with this problem for a while is that it's purely a driver bug.
Currently, the only work-around is to stick with the 17.0.3 version of the driver (which seems to work just fine) until they release a newer driver version which can recover from sleep state without failing. This shouldn't be difficult since they only need to see what changed in that part of the code between version 17.0.3 and 17.1.0. I'm a software developer with driver experience and my guess based on the error messages is that someone is trying to access virtual memory that is paged out when the system wakes from sleep state.
D.