Perform Find on Pressing Enter???

That is exactly what should happen if you press the enter key that is part of the numeric keypad, IF field behavior for that field does not specify that key as a keystroke to move the cursor to the next field. This is a setting in the behavior section of the Inspector. (Data tab)

For windows users: Return = Enter on the Qwerty section of your keyboard and Enter = Enter on the numeric keybad. (And if you have a limited keyboard like this Windows 7 lap top with no number keypad, you can press ctrl-Enter to do an Enter keystroke,)