We had the same problem, we just went along with what everyone does and gave ds baby rice to start. That night we had our first up all night screaming session, and it was like he was really in pain in his stomach. It also made him constipated. I subsequently :roll: heard that it's not the best thing to give as a first food, as it can be very heavy, not so easy to digest, and cause constipation (it's recommended b/c it's pretty tasteless, so can take on the taste of baby's usual milk).
As has been recommended, we left it a couple of weeks, and then tried with pureed fruit & veg (started with sweetpotato, then pears, both of which he loved).