Michelle-
He's still pretty young, so I wouldn't worry too much about it yet. Easier said than done, I know, but keep in mind that it can take 10-15 exposures to a new food before a baby will even THINK about eating it! I'm wondering if it might also be a texture issue...sometimes veggies purees aren't quite as smooth as fruit purees. You might try thinning it out with some breastmilk or formula and to make it pretty runny.
He's still getting plenty of nutrition from breastmilk or formula, and preferences can change in the blink of an eye, so hang in there!