Trigger and sql manager lite 2005

hi,

First, I apologize for the following english ...

I am a very new user of firebird and I got some problems with the triggers.

I have to create a script generating a database schema. The database is Firebird and the GUI SQL Manager Lite 2005.
Everything is ok with the CREATE TABLE, INDEX...But my TRIGGERs doesn't work!

This is my code :
CREATE TRIGGER TABLE1_TRIGGER FOR TABLE1
ACTIVE BEFORE INSERT
POSITION 0
AS
BEGIN
IF (NEW.ItemID IS NULL)
THEN NEW.ItemID = GEN_ID (t1_generator,1);
END;

CREATE TRIGGER TABLE2_TRIGGER FOR TABLE2
ACTIVE BEFORE INSERT
POSITION 0
AS
BEGIN
IF (NEW.SerID IS NULL)
THEN NEW.SerID = GEN_ID (t2_generator,1);
END;

tx_generator are a generators.

I generate this code with the trigger editor, when I commit this statesment, it works fine. But ...

* When I copy this statesment to the file containing the whole database schema, open it in the SQL Editor, SQL Manager stops on my triggers.

* I put the declarations of only 2 triggers in the SQL Editor, then I click on Execute Query : The first trigger is created, the second one fails.

* I put only one statesment, I click on Explain Query : SQL Manager give me the following warning :
Invalid token.
Dynamic SQL Error.
SQL error code = -104.
Unexpected end of command.

* In the same situation as the previous one, I click on Execute Query and the action success

I tried to be as accurate as possible

Best,
Matthias