If you didn't want to go for KEMI interpreters, then likely your config is not having the `request_route { ... }` block and you received a SIP request. See default `kamailio.cfg` for its structure and what should be done in `request_route`.
I enhanced the error log message to be more explicit in this situation. I am closing this one, if you still need assistance, then send an email to sr-users@lists.kamailio.org, the problem to solve is how to use kamailio, not a bug in the code.