I have had this exact same problem, I mean exactly the same. I found out a few things:

1. It takes time, be patient

2. Get under people and push them up. Instead of standing over them and pulling them up. What's the difference ? In the first you are saying "I'm not too good too grab someones foot and boost them up", in the second you are saying " I have arrived now I'm going to drag up to my level of greatness".

3. Sometimes people are distracted and slow because they are a square peg being jammed into a round hole. Not every programmer thrives in the same environment, you have to tailor your management and help style for each individual.