How to workaround backup routine runtime errors?

Hi Experts!

Few years ago I've gently obtained here a very util backup routine that works well with  exception of the fact that frequently some errors occurs when it runs (but it still does the job)

Accordingly with the pictures:

and then

The code:

LOCAL cTempZip, cTempPath, cdia, m.drv
LOCAL oTherm, cThermometer

*-- Close forms
=fecha_forms()


*-- maio 2010 Close work areas
FOR i = 1 TO 100
	SELECT(i)
	use
ENDFOR

cTempZip=""
cTempPath=""

m.drv = m.driver+":"+m.diretor
cSource = ADDBS(m.drv) && This is data path

SET CENTURY on

cdia = DTOC(DATE())
cdia = SUBSTR(CDIA,1,2) + SUBSTR(CDIA,4,2) + SUBSTR(CDIA,7)
*--cDestination = m.drv+cdia+".bak"

cDestination = m.drv+cdia+".zip"

cTempZip = m.drv+'temp'+  '.zip'

cThermometer = 'gsThermometerBar'
oTherm = createobject(cThermometer)
oTherm.lblProgress.caption = "Backup dos dados da Livraria"
oTherm.Show()

DECLARE INTEGER Sleep IN kernel32 INTEGER

IF FILE(cTempZip)
	DELETE FILE (cTempZip)
ENDIF

= STRTOFILE(CHR(80) + CHR(75) + CHR(5) + CHR(6) + REPLICATE(CHR(0),18),cTempZip)

DIMENSION aDBFs(1,5)
nCount = ADIR(aDBFs,cSource+"*.*")
oShell = CREATEOBJECT("Shell.Application")
FOR i = 1 TO nCount

	oTherm.Progress1.Value = INT(i/nCount*100)

	cFileName = aDBFs(i,1)
*--	IF UPPER(RIGHT(cFileName,3)) $ "DBF|FPT" AND NOT ("FOX" $ cFileName)

*-- Fev 2011: Salves .CDX also
	IF UPPER(RIGHT(cFileName,3)) $ "DBF|FPT|CDX" AND NOT ("FOX" $ cFileName)
		oTherm.lblProgress.caption = "Backup => "+ cFileName
		cFile = cSource + cFileName
		nCount1 = oShell.NameSpace(cTempZip).Items.Count
		oShell.NameSpace(cTempZip).CopyHere(cFile)
		DO WHILE oShell.NameSpace(cTempZip).Items.Count = nCount1
			= Sleep(100)
		ENDDO
	ENDIF
ENDFOR

oTherm.Release

RELEASE oShell
COPY FILE (cTempZip) TO (cDestination)
DELETE FILE (cTempZip)
CLEAR DLLS

*-- Find where is the pen drive
IF DISKSPACE("E:\") = -1
	IF DISKSPACE("F:\") = -1
		IF DISKSPACE("G:\") = -1
			IF DISKSPACE("H:\") = -1
				MESSAGEBOX("Não há dispositivo de gravação (pen-drive) disponível para salvar os dados !",48,"Erro")
			ELSE
				lcdrive="H:\"
				COPY FILE &cDestination TO &lcdrive
			ENDIF
		ELSE
			lcdrive="G:\"
			COPY FILE &cDestination TO &lcdrive
		ENDIF
	ELSE
		lcdrive="F:\"
		COPY FILE &cDestination TO &lcdrive
	ENDIF
ELSE
	lcdrive="E:\"
	COPY FILE &cDestination TO &lcdrive
ENDIF

*-- Reabre as áreas fechadas para backup

*-- Some clean-up routines

*----------
=montadic()
*----------

*--- Monta os dicion rios de integridades
*----------

=mont_del()

=mont_atr()
*----------

* Ativa o Help
*******
Do Help
*******

*-- reativa toolbar
fotb   = CREATEOBJECT("cls_toolbar")
fotb.show()

return

Could you point a workaround to that?

Thanks in advance!