Too much protein and iron! Maybe lactose?
Yinka,
I have had the same problem with any sports bars because they have so much protein and iron in them they can make me nauseous... probably because I'm OBVIOUSLY eating them on an empty stomach!
I found that if I just nibble a little at a time and drink lots of fluids I tolerate them much better-- for example, you might just cut the bar in half (try scissors instead of a knife!) and eat only half between meals.
I have lately moved onto protein shakes because I can use a little more milk, little less powder and don't get any nausea at all. I think the milk has a bit of a buffering effect.
The other thought I had is have you ever considered that you might be lactose-intolerant? Some of these sports bars have whey and lactose can come with it -- check the wrapper and see if it says it's low in lactose or lactose-free, just to rule this out.
Good luck!
Dawn P.