I understand 100% of what you are facing. I've recently begun teaching beginner's Aikido classes in my new home town (I was an assistant instructor for two years before moving). I've found that the adults I'm teaching have a fear of falling. When you are young and learning to walk and run, you fall down. Somewhere along the lines of growing up, you are told that falling down is silly and to avoid falling down. Then, you start taking Aikido classes and the first thing the Sensei wants you to learn how to do is fall down. I begin by teaching the adults to roll forward and backward from a kneeling position. I believe the fear most of the adults have is that they will smash their heads into the floor and so by starting from a kneeling position, the fear is lessened. I've also tried using "ukemi" balls, these are large inflatable rubber balls (sort of like a stronger beach ball), this helps teach the students the proper placement of their hands and arms while rolling forward. Teaching people to roll backward is more difficult so I begin by teaching "Koho tento undo" (I'm not sure if you are familiar with this particular exercise or not but it is essentially learning how to fall down backwards without using your hands or arms to stop your fall. Imagine a backward roll without actually rolling backward, instead returning to a standing position). By beginning with this concept, the students learn the initial movements associated with the backward roll. Another idea is to not wear your Hakama while teaching ukemi. I've found that it's important for the students to be able to see my feet and legs while I'm demonstrating proper rolling technique (especially the backward roll) and the Hakama obstructs the view. I usually don't begin instructing the students on how to perform breakfalls until they are comfortable rolling. I've had success using these methods, the adult students are grasping the important concept of ukemi. I'm not sure if you are teaching children or not, but I can honestly say that teaching the children to roll correctly was much less stress-inducing than teaching the adults. Again, I think it's becuase the children don't have that fear of smashing their heads into the floor. I wish you good luck with your Aikido Club and I hope that the information I've provided will help.