Ошибка: Инструкция INSERT EXEC не может быть вложенной

ALTER proc fs_read @pathtoread nvarchar(1024)
AS
SET nocount ON
DECLARE
     @Path nvarchar(1024)
    ,@Fullpath nvarchar(2048)
    ,@Id INT;
IF object_id('tempdb..#tmpfs') IS NOT NULL
    DROP TABLE #tmpfs;
CREATE TABLE #tmpfs(
     id INT IDENTITY PRIMARY KEY clustered
    ,fullpath nvarchar(2048)
    ,subdirectory nvarchar(1024)
    ,depth INT
    ,isfile bit);
INSERT #tmpfs (subdirectory, depth, isfile)
EXEC master.sys.xp_dirtree @pathtoread, 1, 1;
UPDATE #tmpfs 
SET fullpath = @pathtoread;
while EXISTS (SELECT id FROM #tmpfs WHERE isfile = 0)
BEGIN
    SELECT top (1)
         @Id = id
        ,@Fullpath = fullpath
        ,@Path = @pathtoread + '\' + subdirectory
    from #tmpfs 
    where isfile = 0;
    if @Fullpath = @Path
        begin
        insert #tmpfs (subdirectory, depth, isfile)
            exec master.sys.xp_dirtree @Path, 1, 1;
        update #tmpfs
            set fullpath = @Path
            where fullpath IS NULL;
        delete from #tmpfs where id = @Id;
        end
    else
        begin
        set @pathtoread = @Fullpath;
        select top (1)
             @Id = id
            ,@Fullpath = fullpath
            ,@Path = @pathtoread + '\' + subdirectory
            from #tmpfs 
            where isfile = 0;
        insert #tmpfs (subdirectory, depth, isfile)
            exec master.sys.xp_dirtree @Path, 1, 1;
        update #tmpfs
            set fullpath = @Path
            where fullpath IS NULL;
        delete from #tmpfs where id = @Id;
        end
end
--insert #t
select id, replace(fullpath, '\\', '\') as fullpath, subdirectory as filename
from #tmpfs
order by fullpath, subdirectory;
if object_id('tempdb..#tmpfs') is not null
    drop table #tmpfs;
return

CREATE TABLE #t(id INT, fullpath nvarchar(2048), subdirectory nvarchar(1024));
 
INSERT #t -- --
EXEC fs_read 'd:\folder';
 
SELECT * FROM #t
 
DROP TABLE #t

INSERT #tmpfs (subdirectory, depth, isfile)
EXEC master.sys.xp_dirtree @pathtoread, 1, 1;

INSERT #t -- --
EXEC fs_read 'd:\folder';