Odd problem with cursor

Hi,

Have a bit of a problem with a couple of stored procedure (one calls the other) which I use to extract routines from a SQL 2012 database into individual files.  I get an error message about creating the output files when I attempt to extract all procedures, however when I run this for a single procedure (which previously failed) it works.

This is the error: 

Msg 50000, Level 16, State 1, Procedure usp_WriteStringToFile, Line 56
Error whilst Creating file "D:\SQLs\USP_EVENTFUNCTION_UPD.SQL", 

Can't be down to permissions as I get the first 250 of 1000 procedures extracted, then each one fails with the same error.  I wonder if it could be memory, however the error does not back that up. 

Here is the code. 

Calling procedure

ALTER PROCEDURE [Admin].[usp_StoredProcedures_Dump] 
(
	@Path			nvarchar(max),
	@ProcedureName  NVARCHAR(MAX) = NULL,	
	@Schema			nvarchar(64) = NULL,
	@RoutineType	nvarchar(64) = NULL 
)
AS 
BEGIN
	DECLARE @Filename			nvarchar(512) = '';
	DECLARE @SPECIFIC_NAME		nvarchar(512); 
	DECLARE @ROUTINE_SCHEMA		nvarchar(50);
	DECLARE @ROUTINE_TYPE		nvarchar(10);
	DECLARE @ROUTINE_DEFINITION	nvarchar(max);
    DECLARE RoutinesCusor CURSOR FAST_FORWARD READ_ONLY FOR
    	SELECT 
			SPECIFIC_NAME, ROUTINE_SCHEMA, ROUTINE_TYPE, ROUTINE_DEFINITION 
		FROM 
			INFORMATION_SCHEMA.ROUTINES
		WHERE 
				(@ProcedureName IS NULL OR @ProcedureName = SPECIFIC_NAME)
			AND (@Schema IS NULL OR @Schema = ROUTINE_SCHEMA)
			AND (@RoutineType IS NULL OR @RoutineType = ROUTINE_TYPE)
		ORDER BY 
			ROUTINE_NAME ASC;
    OPEN RoutinesCusor;
    FETCH NEXT FROM RoutinesCusor 
		INTO @SPECIFIC_NAME, @ROUTINE_SCHEMA, @ROUTINE_TYPE, @ROUTINE_DEFINITION;
    WHILE (@@FETCH_STATUS = 0)
    BEGIN
		SET @Filename = '';
		IF (ISNULL(@ROUTINE_DEFINITION,'') <> '')
        BEGIN  
			PRINT @SPECIFIC_NAME;
			SET @Filename = UPPER(RTRIM(LTRIM(@SPECIFIC_NAME))) + '.SQL';
			EXEC Admin.usp_WriteStringToFile @ROUTINE_DEFINITION, 'D:\SQLs', @Filename
			--SELECT @@error

			PRINT '---------------------------------------------';
			PRINT '';
        END
        
		FETCH NEXT FROM RoutinesCusor 
			INTO @SPECIFIC_NAME, @ROUTINE_SCHEMA, @ROUTINE_TYPE, @ROUTINE_DEFINITION;  
    END
    
    CLOSE RoutinesCusor;
    DEALLOCATE RoutinesCusor;

END

This is the child procedure (taken from the internet). 

ALTER PROCEDURE [Admin].[usp_WriteStringToFile]
(
	@String			varchar(max), 
	@Path			varchar(255),
	@Filename		varchar(100)
)
AS
BEGIN 

	DECLARE  @objFileSystem int
			,@objTextStream int,
			@objErrorObject int,
			@strErrorMessage Varchar(1000),
			@Command varchar(1000),
			@hr int,
			@fileAndPath varchar(80)

	set nocount on

	select @strErrorMessage='opening the File System Object'
	EXECUTE @hr = sp_OACreate  'Scripting.FileSystemObject' , @objFileSystem OUT

	Select @FileAndPath=@path+'\'+@filename
	if @HR=0 Select @objErrorObject=@objFileSystem , @strErrorMessage='Creating file "'+@FileAndPath+'"'
	if @HR=0 execute @hr = sp_OAMethod   @objFileSystem   , 'CreateTextFile'
		, @objTextStream OUT, @FileAndPath,2,True

	if @HR=0 Select @objErrorObject=@objTextStream, 
		@strErrorMessage='writing to the file "'+@FileAndPath+'"'
	if @HR=0 execute @hr = sp_OAMethod  @objTextStream, 'Write', Null, @String

	if @HR=0 Select @objErrorObject=@objTextStream, @strErrorMessage='closing the file "'+@FileAndPath+'"'
	if @HR=0 execute @hr = sp_OAMethod  @objTextStream, 'Close'

	if @hr<>0
		begin
		Declare 
			@Source varchar(255),
			@Description Varchar(255),
			@Helpfile Varchar(255),
			@HelpID int
		EXECUTE sp_OAGetErrorInfo  @objErrorObject, 
			@source output,@Description output,@Helpfile output,@HelpID output
		Select @strErrorMessage='Error whilst '+coalesce(@strErrorMessage,'doing something')+', '+coalesce(@Description,'')
		raiserror (@strErrorMessage,16,1)
	end
	--EXECUTE sp_OADestroy @objTextStream;
	EXECUTE sp_OADestroy @objTextStream;

END