Dudas sobre CTE (20091013)

Hola a todos,
sigo con un par de dudas con respecto a las CTEs. He estado leyendo en
estos últimos días y más o menos llegué a algo parecido a lo que necesito
pero con algunos errores.
He aquí mi tabla:

CREATE TABLE [dbo].[PROYECTOS](
[IDProyecto] [int] IDENTITY(1,1) NOT NULL,
[Nombre] [varchar](50) NOT NULL,
[Comentario] [varchar](5000) NULL,
[IdPadre] [int] NOT NULL,
[Nivel] [tinyint] NULL,
[IdUsuario] [int] NULL,
[Fecha] [datetime] NULL,
[Mojon] [tinyint] NULL,
[NUMEROHISTORIA] [int] NULL,
[NoEnviarNotificacionesVCS] [tinyint] NULL,
[NoEnviarNotificacionesITS] [tinyint] NULL,
CONSTRAINT [PK_PROYECTOS] PRIMARY KEY CLUSTERED
(
[IDProyecto] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY =
OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

Acá algunos inserts para datos:
SET IDENTITY_INSERT [dbo].[PROYECTOS] ON;
BEGIN TRANSACTION;
INSERT INTO [dbo].[PROYECTOS]([IDProyecto], [Nombre], [Comentario],
[IdPadre], [Nivel], [IdUsuario], [Fecha], [Mojon], [NUMEROHISTORIA],
[NoEnviarNotificacionesVCS], [NoEnviarNotificacionesITS])
SELECT 1, N'People program', N'', 0, 0, 1, '20071025 22:03:49.530', 0,
NULL, NULL, NULL UNION ALL
SELECT 2, N'01- Apps', N'', 1, 1, 1, '20071025 22:04:27.930', 0, NULL,
NULL, NULL UNION ALL
SELECT 3, N'02- Dct', N'', 1, 1, 1, '20071025 22:04:38.650', 0, NULL,
NULL, NULL UNION ALL
SELECT 4, N'06- Clases', N'', 1, 1, 1, '20071025 22:04:44.180', 0, NULL,
NULL, NULL UNION ALL
SELECT 5, N'09- Scripts', N'', 1, 1, 1, '20071025 22:04:49.570', 0, NULL,
NULL, NULL UNION ALL
SELECT 6, N'07- Documents', N'', 1, 1, 1, '20071025 22:05:27.260', 0,
NULL, NULL, NULL UNION ALL
SELECT 7, N'04- Dlls and Exes', N'', 1, 1, 1, '20071025 22:12:40.100', 0,
NULL, NULL, NULL UNION ALL
SELECT 8, N'03- Libs', N'', 1, 1, 1, '20071025 22:12:44.590', 0, NULL,
NULL, NULL UNION ALL
SELECT 9, N'08- Images', N'Images used in the project', 1, 1, 1, '20071026
15:33:27.680', 0, NULL, NULL, NULL UNION ALL
SELECT 11, N'05- Data Files', N'', 1, 1, 1, '20071026 15:33:56.840', 0,
NULL, NULL, NULL UNION ALL
SELECT 12, N'School program', N'', 0, 0, 1, '20071026 15:37:35.950', 0,
NULL, NULL, NULL UNION ALL
SELECT 13, N'01- Apps', N'', 12, 1, 1, '20071026 15:37:46.000', 0, NULL,
NULL, NULL UNION ALL
SELECT 14, N'02- Dct', N'', 12, 1, 1, '20071026 15:37:52.900', 0, NULL,
NULL, NULL UNION ALL
SELECT 15, N'03- Libs', N'', 12, 1, 1, '20071026 15:37:58.420', 0, NULL,
NULL, NULL UNION ALL
SELECT 16, N'04- Dlls and Exes', N'', 12, 1, 1, '20071026 15:38:03.710',
0, NULL, NULL, NULL UNION ALL
SELECT 17, N'05- Data files', N'', 12, 1, 1, '20071026 15:38:20.210', 0,
NULL, NULL, NULL UNION ALL
SELECT 18, N'06- Images', N'', 12, 1, 1, '20071026 15:38:29.340', 0, NULL,
NULL, NULL UNION ALL
SELECT 20, N'07- Help File', N'', 12, 1, 1, '20071026 15:39:07.040', 0,
NULL, NULL, NULL UNION ALL
SELECT 21, N'08- Documents', N'', 12, 1, 1, '20071026 15:41:49.510', 0,
NULL, NULL, NULL UNION ALL
SELECT 22, N'_Corporate Web Site', N'', 0, 0, 2, '20071028 19:57:49.850',
0, NULL, NULL, NULL UNION ALL
SELECT 23, N'_Source files', N'', 22, 1, 2, '20071028 19:58:16.290', 0,
NULL, NULL, NULL UNION ALL
SELECT 24, N'_Libraries', N'', 22, 1, 2, '20071028 19:58:26.890', 0, NULL,
NULL, NULL UNION ALL
SELECT 25, N'_Tools', N'Tools for development', 0, 0, 2, '20071028
19:58:37.600', 0, NULL, NULL, NULL UNION ALL
SELECT 28, N'DbgView', N'sdffsdf', 25, 1, 2, '20071028 19:59:17.870', 0,
2, NULL, NULL UNION ALL
SELECT 29, N'About Pages', N'', 22, 1, 2, '20071028 21:09:44.500', 0,
NULL, NULL, NULL UNION ALL
SELECT 30, N'Product Pages', N'', 22, 1, 2, '20071028 21:09:54.480', 0,
NULL, NULL, NULL UNION ALL
SELECT 31, N'Support Pages', N'', 22, 1, 2, '20071028 21:10:43.310', 0,
NULL, NULL, NULL UNION ALL
SELECT 32, N'Project one', N'', 0, 0, 10, '20081124 16:32:53.400', 0,
NULL, NULL, NULL UNION ALL
SELECT 35, N'Dll tutor', N'', 0, 0, 10, '20090610 11:10:47.120', 0, 999,
NULL, NULL UNION ALL
SELECT 45, N'Apps', N'', 35, 1, 10, '20090612 15:20:06.120', 0, 999, NULL,
NULL UNION ALL
SELECT 46, N'Images', N'', 35, 1, 10, '20090612 18:15:30.460', 0, 999,
NULL, NULL UNION ALL
SELECT 47, N'Dlls', N'', 35, 1, 10, '20090612 18:17:25.150', 0, 999, NULL,
NULL UNION ALL
SELECT 48, N'Libs', N'', 35, 1, 10, '20090612 18:17:32.790', 0, 999, NULL,
NULL UNION ALL
SELECT 51, N'Templates Prueba', N'', 25, 1, 10, '20090614 12:21:40.540',
0, 999, NULL, NULL UNION ALL
SELECT 53, N'prueba 34', N'', 25, 1, 10, '20090614 12:42:23.170', 0, 999,
NULL, NULL UNION ALL
SELECT 54, N'Documentos clarion', N'', 32, 1, 10, '20090701 08:10:50.480',
0, 999, NULL, NULL UNION ALL
SELECT 55, N'Temporary files', N'', 51, 2, 10, '20090712 16:10:22.350', 0,
999, NULL, NULL UNION ALL
SELECT 56, N'MCS', N'', 55, 3, 10, '20090712 16:10:22.450', 0, 999, NULL,
NULL UNION ALL
SELECT 57, N'TDC', N'', 55, 3, 10, '20090712 16:10:22.480', 0, 999, NULL,
NULL
COMMIT;
RAISERROR (N'[dbo].[PROYECTOS]: Insert Batch: 1.Done!', 10, 1) WITH
NOWAIT;
GO

SET IDENTITY_INSERT [dbo].[PROYECTOS] OFF;

Ahora mi CTE:

WITH
Tree (Nombre, Id, Nivel, IdTree)
AS (
SELECT Nombre, IdPadre, Nivel, IdProyecto FROM PROYECTOS
UNION ALL
SELECT P.Nombre, P.IdPadre, P.Nivel, P.IdProyecto FROM PROYECTOS P
INNER JOIN Tree T ON T.Id = P.IDProyecto
)
SELECT SPACE(Nivel*2) + Nombre as data, Id, Nivel, IdTree
FROM Tree

Esta es la que está "más o menos" bien porque da como resultado 77
líneas (cuando en realidad no tengo más de 39 filas en la tabla PROYECTOS)
y si la ejecutan verán que al final empieza a repetir muchas líneas.
Obviamente estoy haciendo algo mal pero no me doy cuenta qué.
Muchas gracias por cualquier respuesta y perdón por el largo del post.
Saludos.

Mauricio
Copenhague, Dinamarca