Delphi 7
IB Objects 4.7?
Firebird 2.01

I have an application that was working fine with FB 1.5 and IB Objects
4.6. Now I have a query that opens fine, but when I refresh it I get
error 335544569 "Column Unknown", Statement TIB_Binding_Cursor ...

The SQL looks like this:

select FIRST 50 Mt.* FROM MyTable Mt
<where clause>
ORDER BY AColumn, AColumn2, Mt.MY_TABLE_ID

The column that is "unknown" is the table's Primary Key: Mt.My_table_ID

How can I fix the problem?