In order for the question to make sense you have to assume that education and attitude are distinct and separate aspects of success, which I do not believe to be true. To me education is fundamentally more about the development of attitudes than it is about the delivery of units of knowledge, skills and information. Therefore my answer to the question as it was asked is both, but a more interesting question is which is more important knowledge, skills and information or attitude.
I put attitude before the acquisition of knowledge, skills, and information because with the appropriate attitude you can always acquire more knowledge, skills, and information. On the other hand just having knowledge, skills, and information does absolutely no good if your attitude is one that prevents you from dealing effectively with reality.
For example take the dogmatic approaches to religion and science that are on opposite extremes of the creationism versus the big bang debate over the origins of the universe. Both sides are mired in attitudes that prevent them from acting with respect for the other people's point of view. The reality is that no one alive today can ever have any direct proof of anything that occurred that long ago, therefore it is ridiculous to destroy your own reputation and possibly the reputations of your opponents through nasty debates over something that no one can answer definitively one way or another.
For me, it's attitude first, always. Once you get your attitude straight then you can always get whatever you need to succeed after that.
My website: www.teach-kids-attitude-1st.com