Subject "Either BOF or EOF is True, or ......"

I follow the wizard to migrate a SQL database to interbase. After I
click the Next button in step "Customize Migration" An alert box with
the message
"Either BOF or EOF is True, or the current record has been deleted.
Requested operation requires a current record." is displayed. I'd
like to ask what is this means and how can I solve it.

Thanks a lot,