aperture

I am new to Aperture.
I have version 1.5 and when I try to use the spot and patch tools they do not respond.I click on the tool but the manifying glass and cross hairs device that allows you to mark the area or spot to change do not appear as shown in the manual and dvd tutorial.
Do I have to do some other step or turn something on for it to work?
Thanks for the help.

Luis