How about something like
VB Code:
  1. Dim DateCheck As Date

  2. If IsNull(txtCost.Text) Then

  3.      rs![Cost]=0

  4. Else

  5.     rs![Cost]=Val(txtCost.Text)

  6. End If

  7.  
  8. DateCheck = IsDate(txtCloseDate.Text)

  9. If DateCheck = True Then

  10.    rs![CloseDate]=CDate(txtCloseDate.Text)

  11. End If