Issues With Read2Go

Hi, I have loaded up some Daisy books into Read2Go, using relevant instructions. When playing an audio book, I find that it reads fine, howeverr, from time to time, skips part of the book and continues as though nothing has happened. I have tried this several times and know that it is missing out part of the story. When this happens, I have usually been listening for several minutes and my iPhone 4S is locked, so I am not inadvertently tapping any navigation buttons. Has anyone else experienced this behaviour with Read2Go and, if so, have you been able to resolve it? If you have a solution or workaround, I would be glad to hear of it. Many Thanks.