When I try to use the processing grass tools like r.series I always get the following messege. I deinstalled QGis and reinstalled the program totally fresh without success.
Is it possible that the data you wish to import is not within the bounds of your GRASS location? You probably need to check over your GRASS location and mapset carefully. When this happens to me I carefully build a new mapset paying particular attention to the map projection and extent required by the data I wish to import.