primary-secondary sync problem

hi guys,

i am new to this DNS business and i'm having a problem.
the setup is bind 9.2.3 is installed on a sun solaris 8 server and is the primary DNS. men and mice suite is installed on another sun solaris 8 and that is our secondary DNS server.
problem is recently the secondary DNS stopped resolving addresses defined on the primary server. sync shoud be automatic but everytime i try to resolve using secondary i get the following error
"*** x.y.com can't find www.mjp.com.sa: Non-existent domain".

a work around this problem i found is to manualy add each domain to the secondary server but i need a permanent solution.

any1 can help plz ?
i dont know what information u guys need to troubleshoot this, so plz tell me and ill update asap.