Please help. In Access 2003 I am trying to calculate a sum of all records of a specific field. I have found the field and unbound the field. I am able to place a specific value in the field but not able to get a sum of the values on my form footer as a total. I keep getting an

The expression may not result in the name of a macro, the name of a user-defined function, or [Event Procedure]
There may have been an error evaluating the function, event, or macro.

Code With Bound Field to Table Field:
'Private Sub Text75_Change()
'Me.Text75.OnChange
'Me.InputParameters (Sum(ChangeOrders.PendingFundedAmount))
'End Sub

'Private Sub Text75_Click()
'Me.Text75 = "2000"
'End Sub

'Private Sub Text75_Exit(Cancel As Integer)
'Me.Text75 = "10000"
'End Sub

Private Sub Text75_Change(Button As Integer, Shift As Integer, X As Single, Y As Single)
Me.DataEntry = False
Me.Text75 = Sum([ChangeOrders].[PendingFundedAmount])
End Sub

When I try the other route unbound I am getting a sub or function not defined:

Private Sub Text75_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
Me.DataEntry = False
Me.Text75 = Sum(Pending2FundedAmount)
End Sub