It's pretty normal for most people's first attempts at elearning not to succeed. Implementing successful elearning in any context is a complex process and every case has its own unique circumstances that can influence it. Many universities are reporting dropout rates as high as 70% for elearning but this can be for a broad range of reasons and contributing factors not related to curricula, e.g. people who opt for elearning courses often do so because they have conflicting commitments.
For more successful curriculum development, the best advice I can recommend is to inform yourself as much as possible about learning and teaching theory, and practice in general, and how computer mediated communication, i.e. elearning, affects this. One area of research that seems to have some promising avenues to explore is Randy Garrison's Communities of Inquiry project at the university of Calgary: http://communitiesofinquiry.com/
In a corporate or professional setting, you'll probably find Reflective Practice (Donald Schon) and the professional development programmes for medical practitioners at McMaster University in Hamilton (HG Schmidt) helpful, as well as Etienne Wenger's work on Communities of Practice: http://www.ewenger.com/. All of these principles have been successfully implemented in elearning and blended learning contexts. This guy sums up Reflective Practice rather well: http://www.learningandteaching.info/learning/reflecti.htm
In implementing and developing elearning programmes, you're going to do a lot of learning yourself. I'd be wary of anyone who claims to have "the answer" or "proven" solutions for elearning issues. Learning and teaching is complex and it's difficult, if not impossible, to establish direct cause - effect relationships between curriculum development and learning outcomes. In this respect, we're all learning and we all depend on each other for finding promising avenues to pursue and share our findings.
Good luck and happy learning!