Loop Through Worksheets And Format Chart 1 - Runtime Error

I wrote a chart formatting macro, which works when applied to a specific sheet, and I'm trying use it in a for each loop. The macro is supposed to loop through a list of sheets and only format chart 1. I'm getting a "run time error 438: object doesn't support this property or method" at this line:

Code:
.ActiveChart.Shapes("TextBox 1").TextFrame.Characters.Text = "Bodily Injury (BI) Liability Claim Trends" & vbLf & " 2005-" & Range("K5").Value & " Percentage Change"

Here is my for each loop:

Code:
Sub UpdateTextAllStateCharts()
'This macro loops through worksheets in a list and performs the assigned task
Dim sheet_name As Range
For Each sheet_name In Sheets("WS").Range("C:C")
If sheet_name.Value = "" Then

[Code] .....

This line is also causing the same error:

Code:
With .Characters(42, 68).Font