Subject "Object is in use" even after reconnecting

I try to create a DB using Delphi 7, JvUIB's components and fbembed.dll (1.5.2, n
ot renamed). I have a script that runs fine with IBExpert (that uses the same fbe
mbed.dll), but running it in my program statement-by-statement I keep getting "Ob
ject is in use" error no matter how I manage a transaction for DML queries: commi
t after each statement or commit after all statements executed. Also I tried to d
isconnect from the DB and connect again to create the FKs, but no success for som
e reason (with the same error). Also I tried to use "built-in" syntax for FKs (i.
e. within CREATE TABLE) - the same result.

Does anybody know what's wrong and how to fix the problem?

Thank you.

Pavel Menshchikov