Unable to change pokemon spawnin gin each zone in XY

[Shakzerr]

I'm trying to change the pokemon appearing in each zone but I want to save this message appears :

Exception Details:
System.OverflowException: La valeur était trop grande ou trop petite pour un UInt16.
à System.Convert.ToUInt16(Int32 value)
à pk3DS.XYWE.MakeSlotData(Int32 species, Int32 f, Int32 lo, Int32 hi) dans D:\a\1\s\pk3DS\Subforms\Gen6\XYWE.cs:ligne 445
à pk3DS.XYWE.MakeEncounterData() dans D:\a\1\s\pk3DS\Subforms\Gen6\XYWE.cs:ligne 457
à pk3DS.XYWE.B_Save_Click(Object sender, EventArgs e) dans D:\a\1\s\pk3DS\Subforms\Gen6\XYWE.cs:ligne 488
à System.Windows.Forms.Control.OnClick(EventArgs e)
à System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
à System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
à System.Windows.Forms.Control.WndProc(Message& m)
à System.Windows.Forms.ButtonBase.WndProc(Message& m)
à System.Windows.Forms.Button.WndProc(Message& m)
à System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Loaded Assemblies:

mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\mscorlib.dll

pk3DS, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
C:\Users\Megaport\Documents\Random Pokémon\RANDOMIZER ROM CITRA\PK3DS\pk3DS.exe

System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System\v4.0_4.0.0.0__b77a5c561934e089\System.dll

System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Windows.Forms\v4.0_4.0.0.0__b77a5c561934e089\System.Windows.Forms.dll

System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Drawing\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Drawing.dll

System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Core\v4.0_4.0.0.0__b77a5c561934e089\System.Core.dll

System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Configuration\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll

System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Xml\v4.0_4.0.0.0__b77a5c561934e089\System.Xml.dll

System.Windows.Forms.resources, Version=4.0.0.0, Culture=fr, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Windows.Forms.resources\v4.0_4.0.0.0_fr_b77a5c561934e089\System.Windows.Forms.resources.dll

pk3DS.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
C:\Users\Megaport\Documents\Random Pokémon\RANDOMIZER ROM CITRA\PK3DS\pk3DS.Core.dll

mscorlib.resources, Version=4.0.0.0, Culture=fr, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\mscorlib.resources\v4.0_4.0.0.0_fr_b77a5c561934e089\mscorlib.resources.dll

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User Message:
An unhandled exception has occurred.
You can continue running the program (albeit with potential side-effects), but please report this error.

Hi, I'm trying to change the Pokemon appearing in each zone but when I want to save this message appears