Code:
Private Sub OKButton_Click()
Dim oTbl As Word.Table
Dim oRow As Row
Dim oRng As Word.Range
Select Case True
Case DescriptionBox = vbNullString
MsgBox "You must enter a description"
Case Not IsDate(DateBox)
MsgBox "You must enter a valid date."
Case PriorityCombo = vbNullString
MsgBox "You must select the priority."
Case Else
Set oTbl = ActiveDocument.Tables(1)
Set oRow = oTbl.Rows.Add
oRow.Cells(1).Range.Text = DescriptionBox.Text
oRow.Cells(2).Range.Text = DateBox.Text
oRow.Cells(3).Range.Text = PriorityCombo.Text
Unload Me
End Select
End Sub