On debug I am receiving the error named in the title of this post. I cannot see why. When I look back at the code it sends me to this function.

Private Function LightChange(Number)
'/===============================================================
'/ This function determines which lights to turn on or off
'/===============================================================
'/ This function
'/ - Determines how many lights to turn on or off
'/===============================================================

'/===============================================================
'/ Variable Declarations
    Dim LNum As Integer
    Dim LControl As Integer
    
'/===============================================================
'/ Variable Value Assignments
    Let LNum = Number
    Let LControl = 1

'/===============================================================
'/ Light switch decision loop
'/ Loop Control Variable: LControl is the LCV
'/ Loop Initialization: At initializaiton LControl is 1
'/ Loop Update: At each iteration of the loop LControl is incremented
'/      by 1.
'/ Loop Termination: At initialization LControl is 1 and is incremented
'/      by 1 at each iteration of the loop. Eventually LControl will be
'/      greater than 5 terminating the loop.
    Do While LControl <= 5
        Select Case LControl
            Case 1
                Switcher LNum
            Case 2
                If LNum > 20 Then
                    Switcher (LNum - 10)
                End If
            Case 3
                If LNum - 1 Mod 10 <> 0 Then
                    Switcher (LNum - 1)
                End If
            Case 4
                If LNum Mod 5 <> 0 Then
                    Switcher (LNum + 1)
                End If
            Case 5
                If LNum < 50 Then
                    Switcher (LNum + 10)
        End Select
    Loop
End Function
And just for completions sake (and because the previous code references it):
Private Function Switcher(Number)
'/===============================================================
'/ This function changes the state of the light indicated by Number
'/===============================================================
'/ This function
'/ - Determines the state of the light
'/ - Changes the state of the light
'/===============================================================

'/===============================================================
'/ Variable Declarations
    Dim LNum As Integer
    Dim State As Boolean

'/===============================================================
'/ Variable Value Assignment
    Let LNum = Number

'/===============================================================
'/ State Determination
    If Me.Controls("Light" & LNum).BackColor = RGB(0, 0, 0) Then
        Let State = False
    Else
        Let State = True
    End If
    
'/===============================================================
'/ State Change
    If State = True Then
        Me.Controls("Light" & LNum).BackColor = RGB(0, 0, 0)
    Else
        Me.Controls("Light" & LNum).BackColor = RGB(255, 255, 0)
    End If

End Function