Is this really a report on the very old FileMaker 7 version or is that simply a reference to the .fp7 file extension? You can see the version of FileMaker that is installed on your machine if you access the help menu and select the "about" option.
Can you describe this issue in more detail?
What file are your using? Is this a starter solution file?
How is the layout designed? What options have been specified for this field in Field behavior?
Pressing Return (The "enter" key that is not part of the number pad on windows keyboards) in a text field, normally starts a new line of text in the same field unless field behavior has been set to respond to this key to exit the field.
A few users with laptops discovered that their keyboards were entering the Numeric Keypad's Enter code instead of the code for the Return key so that is another way you can encounter a change in behavior with this key.