[SR-Users] when dialing another extension, instead of ringing for 30 sec, vmail kicks in right away

I'm using kamailio as a sip proxy and registrar, and freeswitch for all media services like vmail, conference calls, ivrs etc. I just set up vmail ... and it seems to be working.  Except that it appears that I've broken something else because now when I call extB from extA, instead of ringing first for a little while and then having the vmail kick in afterwards, vmail kicks in right away. someone mentioned that it could be a forking problem.  I'm afraid I don't really understand what this means. just wondering if you can point me in the right direction list, as far as what I should be looking for in the kamailio.cfg file... Thanks.