Don't worry if you failed at Management. You couldn't program very well the first time you sat down at a terminal either.
Management takes a different skill set. That's all.
Take a Dale Carnegie Course, read up on basic accounting, and read a book on business management. But, most of all, look at the people you are to supervise, and ask yourself if you can help them.
Toastmasters will also help you. Look for a club.
Managers have to report regularly. Managers also need to keep tabs on what the people below them are doing. Keeping tabs means that they have to have at least a low level ability to do what the people who report to them are doing. So, look for instructional materials on the technologies and systems that your area is using. Failing a few times, with a few people is just part of the learning process.
So, don't be afraid to fail, but Do look for reasons why the failure occurred and avoid that next time.
Also, remember that a good manager helps train the people under him. If you can't help them grow, or if you have not got someone who can replace you, at least partially, then you are not doing your job.
If YOUR Boss isn't willing to help you with these things, then, you are in a sacrificial position.
So, good luck with it all.
But remember, Technology is a rapidly changing field. Whatever you are doing now, it will be obsolete within five years. If you are tired of learning new stuff, then it's time to get a sales job. If you do find excitement in learning new things, then keep at what you are doing now.