MAMP and BP

Hi,
I have MAMP PRO installed. Installed WP MU and (hopefully) BP. When I browse the site it shows up well. But when I try to SIGN UP I got the error

'The requested URL /tangosfer/register was not found on this server.
the URL in the browser is http://localhost/tangosfer/register'

or AFTER LOGGING IN and then go to activity, forums, etc. that they were not found in the server.
(The requested URL /tangosfer/members/tangosfer/activity/ was not found on this server.)
The browser address shows: http://localhost/tangosfer/members/tangosfer/activity/

Can anyone help, please?
Thanks Aydogan

PS: single site is running well so far...