Resolution:
Somewhere in your code you are creating your own message type and assigning it the number 1000 . It would look like this in C:

mt = TipcMtCreate("some_record",1000, "str");

Note: the third argument can be any valid SmartSockets message type grammar. See the SmartSockets User’s Guide, Chapter 1,  Messages -> Standard message types.

Somewhere else in your code you are reusing  the number 1000 when creating a new message type. This is not allowed, each message type must have a unique number. To reuse the number for a new message type you first would have to destroy the existing message type which uses that number.

TipcMtDestroy(mt)