To get that message you'd have to get a network error from the OS (and I guess we haven't removed a lot of old error strings).
I seem to be able to work around the problem by converting the image I want to halftone into a smart object. That said, the error has popped up again a few times, especially when I've tried to apply the filter to an object that's larger than the canvas. I have to crop it to the canvas size and then it seems to work. The message has also popped up doing other random things.
It seems to be connected to lack of space for my scratch disks more than anything (though correlation is not causation so who knows). What that has to do with a network error God alone knows though.
I had the same issue and I fixed it by flattening and shrinking the size of my image. I'm not sure what the size/dpi threshold is for this bug to kick in, but I reduced my image from 80"x80" @ 300dpi to 60"x60" @ 300dpi and the filter worked without a problem.
I hope this helps.