How long did you wait? you could be on an unlucky streak.

That said 45 kh/s is quite low, 64bit miners are usually at 80 kh/s per core and more (using minerd64_sse4), on a quad-core cpu, unlucky streaks can last 3 minutes between shares (on http://fairpool.co.vu:9640/).

If you have only 2 cores at 40 kh/s, I guess that could translate to 12 minutes for unlucky streaks, which is quite long