CheckBox161_CheckedChanged - Handles clause requires a WithEvents variable defined in the containing type or one of its base types

I just can't seem to find the error with these checkboxes.
Error: Maximum number of errors has been exceeded. File vbc:

Output: C:\Users\...\Documents\Visual Studio 2008\WebSites\WebSite1\Weight.aspx.vb(31,0): error BC30506: Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
The output error was listed for every single checkbox
Declaration:
Imports System
Imports System.Web
Imports System.Web.UI.WebControls
Imports System.Data.SqlClient
Imports System.Configuration

Partial Class weight
    Inherits System.Web.UI.Page
    Dim SelFactor As String
    Dim llcombine As String
    Dim llcontinue As String

Checkbox code:
Protected Sub CheckBox161_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles CheckBox161.CheckedChanged
 & ...