Passing a parameter to a SQL statement with Oracle Database

Hello,
I am using an Oracle Database.
I am trying to pass a parameter to the SQL statement.

My orginal SQL which gets the records is as follows:
SELECT rug.user_group_id, rug.user_group_desc, rh.code_hotel
FROM rpt_user_groups rug, rpt_user_group_xref rugx, rpt_hotels rh
WHERE rugx.rpt_user_group_parent_id in 1 <-------------------i have to pass a parameter here instead of 1
AND rugx.rpt_user_group_child_id = rug.user_group_id
AND rug.user_group_id = rh.user_group_id(+) ORDER BY rug.user_group_desc,rug.user_group_id

i am trying like below:

Protected Sub RadTreeView1_NodeExpand(ByVal sender As Object, ByVal e As RadTreeNodeEventArgs) Handles RadTreeView1.NodeExpand
Dim oradb As String = "Data Source=(DESCRIPTION=(ADDRESS_LIST=" _
                                 + "(ADDRESS=(PROTOCOL=TCP)(HOST=)(PORT=1521)))" _
                                 + "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=something)));" _
                                 + "User Id=something;Password=something;"
 Dim conn As New OracleConnection(oradb)
        conn.Open()

Dim sql As New OracleCommand("SELECT rug.user_group_id, rug.user_group_desc, rh.code_hotel FROM rpt_user_groups rug, rpt_user_group_xref rugx, rpt_hotels rh WHERE rugx.rpt_user_group_parent_id in @ParentId AND rugx.rpt_user_group_child_id = rug.user_group_id AND rug.user_group_id = rh.user_group_id(+) ORDER BY rug.user_group_desc,rug.user_group_id", conn) ' VB.NET

        sql.Parameters.Add("@ParentId", e.Node.Value)
        Dim adapter As New OracleDataAdapter(sql)  --- my parameter is not replaced with '1'
Dim data As New DataTable()
adapter.Fill(data)    <----- fails here with message (An exception of type 'Oracle.DataAccess.Client.OracleException' occurred in Oracle.DataAccess.dll but was not handled in user code.Additional information: External component has thrown an exception.)

End Sub


when i execute the query i get a error pop-up:  ORA-00936  missing expression

any help would be greatly appreciated.
anagm