Microsoft Outlook - Email Hyperlink Problems
When you click a hyperlink in Microsoft Outlook email an error is displayed saying :-
“This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.”
This is caused by a registry corruption after you have upgraded to Microsoft Internet Explorer 6 or 7
You should be able to repair this problem by reseting the Internet Explorer Web Settings.

For more information refer to the Microsoft support article
http://support.microsoft.com/kb/310049