I've just tried my application against FB2.
The first error I get when preparing a pretty vanilla query is

ISC ERROR CODE:335544569
ISC ERROR MESSAGE:
Dynamic SQL Error
SQL error code = -206
Column unknown
RDB$INDEX_SEGMENTS.RDB$FIELD_NAME
unknown ISC error 336397208

Now I can see in both the FB1.5 and FB2 databases, system tables that
RDB$INDEX_SEGMENTS has the field RDB$FIELD_NAME.
So where do I go to from here? Why on earthe would there be an error telling
me the column does not exist?

Alan