Oracle Forms

Hello,
I'm starting to learn how to use Forms, in Oracle 10g. I am attempting to do a CREATE USER statement in PL/SQL, with no luck.

What I have is a Form with a Data Block. There are two items in that block, from a table in the database. Also in the Data Block is a button. This button has one trigger: WHEN-BUTTON-PRESSED.
In the PL/SQL for this trigger, I want a 'CREATE USER <blah> IDENTIFIED BY <blah>' SQL statement.
ALL_USERS is the name of my Data Block.
USERNAME is the name of an item in the Data Block.

My attempts so far:
'CREATE USER :ALL_USERS.USERNAME IDENTIFIED BY :ALL_USERS.USERNAME';
both with and without the single quotes doesn't work, and adding
BEGIN

END
around the statement doesn't work.

I tried a couple of other ways suggested online:

EXECUTE IMMEDIATE 'CREATE USER :ALL_USERS.USERNAME IDENTIFIED BY :ALL_USERS.USERNAME';
but get the error message 'This feature is not supported in client-side programs'

I've also tried

DECLARE

cur integer;

BEGIN

cur := DBMS_SQL.OPEN_CURSOR;
DBMS_SQL.PARSE(cur, 'CREATE USER jim IDENTIFIED BY jim', DBMS_SQL.NATIVE);
DBMS_SQL.CLOSE_CURSOR(cur);

END;

This time, I got a 'Implementation Restriction: 'DBMS_SQL.NATIVE' cannot access remote package variable or cursor


Is it possible to do this kind of statement in PL/SQL? If so, can anyone out there tell me how? Any assistance would be greatly appreciated.

Regards,
James.