This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.

To resolve above mentioned error while opening any of hyperlinks in Ms Excel, Outlook, etc just follow this step :

For Windows XP (Service Pack 1 and higher)

* Click Start, Control Panel, double-click Add or Remove Programs
* Click Set Program Access and Defaults
* Click Custom
* Under Choose a default Web browser, select Internet Explorer
* Click OK

For Windows Vista

* Click Start, and click Default Programs
* Click Set program access and computer defaults
* Click Custom, select Internet Explorer and click OK
* Close and re-open Microsoft Outlook