In the fantastic new stats pages in 0.91 what are the 'query had unnecessary overhead' packets I am dropping so many of?

Out of 1.8M of Query packets that have hit my machine in the last hour, I've dropped 1.4M. Of these, 83% are because of that 'unecessary overhead' clause.

Meanwhile I am getting very few search results and having poor network connection stability.

Are these things related?

Nos