russell, 
 
If you want to use arrays then you need to learn about loops too!  
 
Take a look at this - I think it mirrors what you were trying to do, but with rather more compact code:  
 #include <ComboConstants.au3>
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
Global $reportfile = "C:WindowsTemp"
Global $box[8], $field[8]
#region ### START Koda GUI section ### Form=
	$Form1 = GUICreate("Form1", 492, 395, 903, 134)
	; Use an array to hold the combo ControlIDs as well - then we can loop through them
	For $i = 0 To 7
		$field[$i] = GUICtrlCreateCombo("", 16, 32 + (24 * $i), 81, 25)
		GUICtrlSetData(-1, "yes|no")
	Next
	GUISetState(@SW_SHOW)
#endregion ### END Koda GUI section ###
While 1
	$nMsg = GUIGetMsg()
	Switch $nMsg
		Case $GUI_EVENT_CLOSE
			Exit
	EndSwitch
	Sleep(10000)
	ExitLoop
WEnd
; Now we can loop through the combos and read them
For $i = 0 To 7
	$box[$i] = GUICtrlRead($field[$i])
	If $box[$i] = "yes" Then
		; Not quite sure what you wanted to write to the file - you should be able to see what the various options are from this.
		MsgBox(0, "Writing", $reportfile & "acc" & $i & ".txt" & @CRLF &  "account" & $box[$i])
	EndIf
Next
Please ask if you have any questions.  
 
M23