It is navigable but could be far better. The whole "Become a Member" and "The Content you are trying to see is available only for members of our site..." is misleading. And there are redundant links to creating an account. My suggestion:
1) in navigation bar along top of front page put "Membership"
2) on the membership page have
A) "Existing Members Login" on the left and "New Member Registration" on the right, then remove the "Create an account" from the bottom of the left (Login) side of the page (it is redundant); or
B) on membership page keep the left hand side as it is, then change right hand side to say "Please login or create a new account" without a link.