EDBEngineError - Capability not suppport

Please help!

My program has a pair of master/detail Interbase tables.  When I
tried to flush the modifications to the tables with
Database.ApplyUpdates([Master, Detail]), an error message
'Capability not support' was shown.

It's very strange that the program works fine if there is no
amendment on the detailed table.

Thanks for any comments.

Regards,

Jason.