DllCall error [Unknown]

#include <ButtonConstants.au3>
#include <EditConstants.au3>
#include <GUIConstantsEx.au3>
#include <SliderConstants.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>

$Form1 = GUICreate("AutoIT", 332, 379, 211, 161)
GUICtrlSetFont(-1, 8, 800, 0, "MS Sans Serif")
$Group1 = GUICtrlCreateGroup("File ", 8, 40, 313, 137)
$Label2 = GUICtrlCreateLabel("Input:", 16, 67, 31, 17)
$Input1 = GUICtrlCreateInput("", 64, 64, 201, 21)
$Label4 = GUICtrlCreateLabel("Seed:", 16, 139, 32, 17)
$Input3 = GUICtrlCreateInput(Random(100, 999, 1), 64, 136, 145, 21, BitOR($GUI_SS_DEFAULT_INPUT,$ES_NUMBER))
$Button1 = GUICtrlCreateButton("...", 272, 64, 27, 21)
$Input4 = GUICtrlCreateInput("", 64, 112, 201, 21)
$Label9 = GUICtrlCreateLabel("Icon:", 16, 116, 28, 17)
$Button5 = GUICtrlCreateButton("...", 272, 112, 27, 21)
$Button4 = GUICtrlCreateButton("Test", 128, 344, 75, 25)
GUISetState(@SW_SHOW)

While 1
$nMsg = GUIGetMsg()
Switch $nMsg
Case $GUI_EVENT_CLOSE
Exit
Case $Button5
$File2 = FileOpenDialog("Choose the Icon", @ScriptDir, "Icons (*.ico)")
GUICtrlSetData($Input4, $File2)
Case $Button1
$File = FileOpenDialog("Choose the File", @ScriptDir, "Sources (*.au3)")
GUICtrlSetData($Input1, $File)
Case $Button4
$read = GuiCtrlRead($Input3)
$seeder = _Call($read)
MsgBox(0,"", "DONE!")
EndSwitch
WEnd

Func _Call($addseed)
$xxcount = Int($addseed/100)
MsgBox(0,"",$addseed & @CRLF & $xxcount)
$keys = DllCall("Project21.dll", "int", "AddIntegers", "int", $addseed, "int", $xxcount)
Return $keys[0]
EndFunc