We have just upgraded some of our servers to 1.5.2. Of the many
databases we have, we can no longer connect to 3 databases with
IBManager even after we backed up and restored them on the new server.
When we tried to connect, IBManager would displayed 4 error msgs
sequentially, all has to do with error code 901 and the sql it tried.
Here is one of them:

select RDB$FIELD_NAME
, RDB$SYSTEM_FLAG
from RDB$FIELDS
where RDB$SYSTEM_FLAG = 0
order by RDB$FIELD_NAME

I had no problem connecting via IBWISQL and running these sql statements.

If I uninstall 1.5.2 and reinstall 1.0 I would be able to connect to
these databases again. But that is not the solution in the long run as
I use my workstation for developing databases and would like to run 1.5.2.

Any thoughts would be appreciated.

Jung