This happens when you have foreign keys created in such a way that there is a circular reference. So that you will have a database that looks something like..
Table_A has a foreign key to Table_B
Table_B has a foreign key to Table_C
Table_C has a foreign key to Table_A
I'd be very wary of synchronising data in these circumstances and thoroughly review your database schema. Have a look at SQL Dependency Tracker (ok I would say that wouldn't I ) http://www.red-gate.com/products/SQL_De ... /index.htm. This will give you a visual representation of your database and may help you track down any issues you have.
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