It seems like WaT is no match for Koda Kumi.
Hava Rava debuts at #4, with 64,000 copies.
http://www.oricon.co.jp/news/ranking/30688/For comparisons, here are the 1st week sales of the previous singles:
2,000 Sotsugyou TIME 2004/2/18
86,000 Boku no KIMOCHI 2005/11/2
124,000 5 centi. 2006/1/25
In essence, Hava Rava did worse than their first two singles (and may ultimately sell less than the other two).
I think it's mainly because of the lack of the Kouhaku/debut effect and lack of actual promotion before the single release (heck, PV wasn't shot till two weeks before). Personally, I agree that it's the worst out of their 3 singles.