MyBB Community Forums

Members are not getting their activation email, also how can I make it from a specific email a address such as [email protected]? Also can I make lets say 150 threads per 1 page?

Try this: http://wiki.mybb.com/index.php/Help:Mail

You can also activate the member's account through the ACP. Usernames & Groups>Click the user>Activate.

For the threads do this:
ACP>Configuaration>Forum Display>User Selectable Threads Per Page>Put 150 to the list.