Problem with SQLCA.SQLERRD[2] and Oracle

Hi all,
I have the following problem.

I insert a row in a table that have a field defined "SERIAL", then I use 
the SQLCA.SQLERRD[2] to receive the value inserted for the serial.
The value returned is -1.
The table has the trigger and sequence for the simulation of the 
Informix serial and are enabled.

I attach a sample:

DATABASE PRACTOR
MAIN
   DEFINE vl_integer INTEGER
	        

   CREATE TEMP TABLE temp (unico SERIAL,
                           dta   DATE )    
   INSERT INTO temp (dta) VALUES (TODAY)
   LET vl_integer = SQLCA.SQLERRD[2]
   DISPLAY vl_integer

   DROP TABLE temp
   CREATE  TABLE temp (unico SERIAL,
                           dta   DATE )    
   INSERT INTO temp (dta) VALUES (TODAY)
   LET vl_integer = SQLCA.SQLERRD[2]
   DISPLAY vl_integer
   DROP TABLE temp
END MAIN


The Fourj's runtime version is 3.54 for Windows
The server is a Windows 2000
The database is Oracle 8.1.7.4.1

Can anyone helps me?
Thank you

Giovanni Zuliani
SMC TREVISO SRL