I am trying to write a value to the \"A1\" cell, but am getting the following error:
Application-defined or object-defined error \'1004\'
I think you may be getting tripped up on the sheet protection. I streamlined your code a little and am explicitly setting references to the workbook and worksheet objects. In your example, you explicitly refer to the workbook and sheet when you're setting the TxtRng object, but not when you unprotect the sheet.
Try this:
Sub varchanger()
Dim wb As Workbook
Dim ws As Worksheet
Dim TxtRng As Range
Set wb = ActiveWorkbook
Set ws = wb.Sheets("Sheet1")
'or ws.Unprotect Password:="yourpass"
ws.Unprotect
Set TxtRng = ws.Range("A1")
TxtRng.Value = "SubTotal"
'http://stackoverflow.com/questions/8253776/worksheet-protection-set-using-ws-protect-but-doesnt-unprotect-using-the-menu
' or ws.Protect Password:="yourpass"
ws.Protect
End Sub
If I run the sub with ws.Unprotect commented out, I get a run-time error 1004. (Assuming I've protected the sheet and have the range locked.) Uncommenting the line allows the code to run fine.
NOTES:
Cells(1, 1) notation can cause a huge amount of grief. Be careful using it. Range("A1") is a lot easier for humans to parse and tends to prevent forehead-slapping mistakes.