Th Gridline option will only become available after you select a control that has a "Layout" applied...
For example:
In an Access 2007 format DB, if you create a simple tabular report using the wizard there will be a "Layout" applied.
You can go into Design View (or Layout View) and select any control in the layout and the Grilines option will become available.
If you are *sure* that no layout exists (This report was imported from Access 2003,or the layout was removed manually) You can select all the controls you want in the Layout and click: Arrange-->Control Layout-->
...then select eithe Tabular or Stacked.
Then if you click on any control in the Layout, the Gridline options will be available
;-)
JeffCoachman