Application or object defined error when trying to change background and font colors - vba

Question

I am trying to replace all of the conditional formatting of a spreadsheet (over 30 formatting rules). I have created a class module (called ConditionalFormatting) that has a series of subs for all the formatting rules, with one sub for each range that needs conditional formatting.
The only way I have thought to do this (open to suggestions) is by having the worksheet_change event call a sub in the ConditionalFormatting class called FormattingSubs which will call the correct sub to perform the formatting.
Here is the code for FormattingSubs:
Public Sub FormattingSubs(target As Range)
'have logic here to call the right sub based on what target.address
'is from the worksheet.change event
Select Case target.Name.Name
Case "head_pouch_lot_number"
Call HeadPouchLotNumber(target)
Case "head_consumed_pouch_lot"
Call HeadConsumedPouchLot(target)
Case "section_one_heading"
Call SectionOneHeading
End Select
End Sub
And here is the code for one of the formatting subs, HeadConsumedPouchLot: (note that the color variables are public constants defined in a separate module)
Public Sub HeadConsumedPouchLot(target As Range)
Dim head_consumed_pouch_lot As Range
Dim ws As Worksheet
Set head_consumed_pouch_lot = ActiveSheet.Range("head_consumed_pouch_lot")
Set ws = target.Worksheet
If target.address <> head_consumed_pouch_lot.address Then
Set target = head_consumed_pouch_lot
End If
With ws.Range(target.address)
If Range("section_one_heading").Value <> "" Then
.Interior.ColorIndex = red
.Font.ColorIndex = yellow
Else
.Interior.ColorIndex = lightgreen
.Font.ColorIndex = black
End If
End With
The problem is that when it goes to actually set the color, it gives me the 1004 error: "Application-defined or object-defined error."
What is wrong with my code?

Answer 1

The problem I figured out was that I needed to unprotect my sheet before I could make any changes to it! Thank you all for helping me look for answers.