Htree - many hours later still getting "invalid query for htree"

Question

I'm using the Pre_Form trigger ftree.populate_tree('HTREE_BLK.TREE4'); and the query you see below. I am still getting "FRM-47313: Invalid query for the hierarchical tree". I must be missing something because I don't see what is wrong with the query.
greg
SQL> select
2 decode(level, 1, 1, -1)
3 ,level
4 ,description
5 ,null
6 ,menu_id
7 from htree_menu
8 start with belongs_to is null
9 connect by prior
10 menu_id = belongs_to;
DECODE(LEVEL,1,1,-1) LEVEL DESCRIPTION N MENU_ID
1 1 Retired Profit Sharing System 1
-1 2 Screens 2
-1 3 Main 5
-1 3 Search 6
-1 2 Processing 3
-1 3 Apply Interest 7
-1 3 Calculate Quarterly Payments 8
-1 3 Six Month Projections 9
-1 2 Reports 4
-1 3 Summary Report 10
-1 3 Monthly Payments 11
DECODE(LEVEL,1,1,-1) LEVEL DESCRIPTION N MENU_ID
-1 3 Participant Listing 12
-1 3 Participant Quarterly Report 13
-1 3 Six Month Projection 14
14 rows selected

Answer 1

I tried this select on the SCOTT schema:
select decode(level,1,1,-1),level,ename,null,empno from emp connect by prior empno=mgr start with mgr is null
In a pre-form in Oracle9i Forms and it works for me.
Check this select in your case.
Make sure that you don't have any extra characters in the select (";")