Basically, a junior member is 1 to 30 posts. Once a person has posted 30 times he becomes a member. The only reasoning is that new people can see who has posted a number of times and therefore may be reagarded as someone helpful and/or a reasonable contributor to this site. Your post made it through this time so perhaps the system glitched when you tried to originally post.

And because of that post, you now have, as many of us have referred to it as, while working our way to member, "one brownie point".