Outlook 2007 cannot sort by task subject field

I recently switched from Office 2003 to Office 2007.
In Outlook 2003 I was able to sort my Tasks based upon their names (Subjects), but in Outlook 2007 I get the following error message:
“You cannot sort by this field”

To resolve if you need to remove Task Subject from the view and replace it with Subject.

1. Right click on the column heading
2. Select customise current view
3. Click on fields
4. Add subject, remove task subject
5. Now it you will be able to sort by the subject field