Do I declare $vars multiple times?

#include 
#include 
#include 
#include 

Opt("GUIOnEventMode", 1)
Opt("MustDeclareVars", 1)
OnAutoItExitRegister("_exit")

Global $aQueue[1][3]
Global $aTasks[5][2]
Global $sScriptstatus

Global $hGUI = GUICreate("Aufgabenliste", 250, 390)

Global $iCounter_label = 0
Global $hCounter_label = GUICtrlCreateLabel("0", 50, 72, 200, 20)
Global $hLoadBtn = GUICtrlCreateButton("Load", 140, 40, 100, 30)
Global $hStartBtn = GUICtrlCreateButton("Start", 30, 5, 50, 30)
Global $hStopBtn = GUICtrlCreateButton("Stop", 30, 40, 50, 30)

GUISetState(@SW_SHOW, $hGUI)

GUICtrlSetOnEvent($hLoadBtn, "_load")
GUICtrlSetOnEvent($hStartBtn, "_check")
GUICtrlSetOnEvent($hStopBtn, "_stop_working")
GUISetOnEvent($GUI_EVENT_CLOSE, "_exit", $hGUI)


While 1
Sleep(100)
WEnd

Func _load()
$aQueue[0][0] = "0"
$aQueue[0][1] = "18/01/2013 08:00:00"
$aQueue[0][2] = "Test"
EndFunc ;==>_load

Func _check()
$sScriptstatus = True
AdlibRegister("_compare_datetimes", 1000)
EndFunc ;==>_check

Func _compare_datetimes()
Local $aRow, $next_date, $aDate
If UBound($aQueue) = 0 Then
_stop_working()
Return 0
EndIf
$aRow = StringSplit($aQueue[0][1], " ")
$next_date = $aRow[1]
$aRow = StringSplit($aRow[2], ":")

$aDate = StringSplit($next_date, "/")

If $aDate[3] * 365 + $aDate[2] * 30 + $aDate[1] = @YEAR * 365 + @MON * 30 + @MDAY Then
If $aRow[1] * 3600 + $aRow[2] * 60 = @HOUR * 3600 + @MIN * 60 + @SEC Or $aRow[1] * 3600 + $aRow[2] * 60 < @HOUR * 3600 + @MIN * 60 + @SEC Then
$aRow = 0
$aDate = 0
_start()
EndIf
ElseIf $aDate[3] * 365 + $aDate[2] * 30 + $aDate[1] < @YEAR * 365 + @MON * 30 + @MDAY Then
$aRow = 0
$aDate = 0
_start()
EndIf
$iCounter_label = $iCounter_label + 1
GUICtrlSetData($hCounter_label, $iCounter_label)
$aRow = 0
$next_date = 0
$aDate = 0
EndFunc ;==>_compare_datetimes

Func _start()
Local $sError, $sStatus, $ShellExecute
Local $aBatch[5][5] = [[1, 1, $aQueue[0][1], "Task 1", ""], _
[2, 2, $aQueue[0][1], "Task 2", ""], _
[3, 3, $aQueue[0][1], "Task 3", ""], _
[4, 4, $aQueue[0][1], "Task 4", ""], _
[5, 5, $aQueue[0][1], "_create_next_date", ""]]

ReDim $aTasks[5][2]
For $i = 0 To UBound($aBatch) - 1
$aTasks[$i][0] = $aBatch[$i][1] * 10
$aTasks[$i][1] = $aBatch[$i][3]
Next


For $i = 0 To UBound($aBatch) - 1
$sStatus = " ... started"
If $aBatch[$i][4] = "" Then
$sError = " "
_write_log($sError, $aBatch[$i][4], $sStatus)
$sError = "OK"
$sStatus = " ... finished"
_write_log($sError, $aBatch[$i][4], $sStatus)
Else
$sError = " "
_write_log($sError, $aBatch[$i][4], $sStatus)
$ShellExecute = Run($aBatch[$i][4], "c:", @SW_HIDE)
If $ShellExecute <> 0 Then
$sError = "FEHLER"
$sStatus = " Something went wrong."
Else
$sError = "OK"
$sStatus = " ... finished"
EndIf
_write_log($sError, $aBatch[$i][4], $sStatus)
EndIf

If UBound($aTasks) = 1 Then
$aTasks[0][0] = ""
$aTasks[0][1] = ""
Else
_ArrayDelete($aTasks, 0)
EndIf
Next
Sleep(1000)

If UBound($aQueue) = 1 Then
$aQueue[0][0] = ""
$aQueue[0][1] = ""
$aQueue[0][2] = ""
Else
_ArrayDelete($aQueue, 0)
EndIf
$sError = 0
$sStatus = 0
$ShellExecute = 0
$aBatch = 0
_load()
EndFunc ;==>_start

Func _stop_working()
AdlibUnRegister("_compare_datetimes")
$sScriptstatus = False
Return 0
EndFunc ;==>_stop_working

Func _exit()
Exit
EndFunc ;==>_exit

Func _write_log($sError, $sCommand, $sStatus)
Local $hFile
$hFile = FileOpen("log_woBATCHwoSQLwoLV.txt", 1)
FileWriteLine($hFile, "[" & @MDAY & "/" & @MON & "/" & @YEAR & " " & @HOUR & ":" & @MIN & ":" & @SEC & "][" & $sError & "] " & $sCommand & " " & $sStatus)
FileClose($hFile)
EndFunc ;==>_write_log