C.C.
Oh boy! Been there! My son will be 10 in April and just learned to ride last September w/out training wheels. For a long time he would just refuse to get on the bike. He would cry and have a meltdown if I tried to force him. I would have him just get on the bike to see how much he has grown, and tell him he only had to sit on it. He was more comfortable when he could put his feet almost flat to the ground. I borrowed a friends' son's smaller bike and let him sit on that and push himself along with his feet. I was sweeping the driveway, pretending not to pay attention as he scooted along and then eventually put his feet on the pedals and went. I couldn't believe it and was so proud of him for overcoming that fear. It was like teaching him to swim. At the time they don't want to do it, but they will thank you for it later as they take off with their friends.
I would say be patient, Try a smaller bike or look into a balance bike. I had a friend that bought a cheap bike from Goodwill and removed the pedals and chain(made it into her own balance bike) and let her son get the hang of it that way. He was riding his own bike later that day! You can also try going to a soccer field with the short/cushy grass and see if he is willing to try riding there and will land on the grass if he falls.
Good luck!