BUG #4790: ENUM word not recognized!

The following bug has been logged online:

Bug reference: 4790
Logged by: Piergiorgio Buongiovanni
Email address: p(dot)buongiovanni(at)net-international(dot)com
PostgreSQL version: 8.3
Operating system: Server Linux and client Windows
Description: ENUM word not recognized!
Details:

I'm using Query Tool of pgAdmin III and trying to execute this:

CREATE TYPE business.EuropeanCEFLevel AS ENUM
('A1','A2','B1','B2','C1','C2');

but the following error is raised:

ERROR: syntax error at or near "ENUM"
LINE 1: CREATE TYPE "business.EuropeanCEFLevel" AS ENUM ('A1','A2','...
^
********** Errore **********

ERROR: syntax error at or near "ENUM"
Stato SQL: 42601
Carattere: 44

What's the problem?
Regards