However, it seems you have some problems with your mail setup if it will not send out confirmation emails. In the future, please don't make 3 or more threads all concerning the same issue - yes, confirmation emails and notifications are not exactly the same, but the coherent problem is that the site is not sending the emails, right? Then it is probably the same cause and should only have one support thread.
Generally speaking, XOOPS should be excellent for Intranets.