My guess would be... Different databases, requiring export from IWZ to some CSV or XML file and import tools to put stuff back into FKG, all of which may not yield correct or expected results on some side and needs to be debugged.
No, I don't think the two databases are actually linked. I doubt they're even the same type of database. Wouldn't amaze me if IWZ ran on the MS SQL Server and FKG ran on MySQL instead.