Maximum of three 3 Ad units per page (Size or color does not matter) and i Link ad unit and also its fine to place google search with them!
May he saw a sudden surge in traffic and checked the source to find out about this discussion and changed the format . ~G
max 3 ad blocks and 1 ad link unit is allowed per page If you want to know more visit astace.blogspot.com it has cleared every anxities I got. maybe it will help you.
this site is doing think against the adsense tos. you are allowed to use 3 ads units on a single page