[asterisk-users] "Dropping call because extensions '200', 's' and 'i' doesn't exists"

[s m]

hello all
i,m newbie in asterisk and now want to sip and h323 connection.
this is my scenario:
phone(ext100)--->freepbx---sip--->system1---H323--->system2--->freepbx--->phone(ext200)

when i call 100 from 200, every thing is ok and phone is ringing but
when i call 200 from 100, it says "service unavailable".

i debug asterisk in my system 2 and see below message:
 "Dropping call because extensions '200', 's' and 'i' doesn't exists
in context [from-trunk]"

i googled about this message and found that file
extensions_mor_h323.conf should be included into
/etc/asterisk/extensions_mor.conf. but i don't have any
extensions_mor.conf file at all!!!
is extensions_mor.conf really necessary to fix my problem?if yes, how
i have connection in one way without this file? if no, how i can fix
this problem?
thanks in advance
sam