no activation email no new blogs created

hi i am having problems with activation for wordpress mu
it shows successfully created new blogs in the interface level. however, it doesnt send out activation email, also no database created for new blogs. the only change is there are new data in wp_signups table

can anyone help me on this plz?

i am using wordpress mu 2.8.6 + buddy press 1.1.3 with default theme at the moment

regards

george