I'm having the same problem. I get the following error message in a text file:

Application start: 2008-8-3 2.40.19Silent modeMode 1, short infoSubmitting activation request...Download: successResult parsing error (2)Error activating the productPlease check the serial number that you have entered and ensure that it is associated with the email you used. Try to activate the product again. If you are using Stardock Central you can right-click on the product and attempt to activate without reinstalling. Please include this log file when contacting support@stardock.com.Using silent activation with null serial mode.

Before you ask, yes, I am using the correct email address and the activation key is copied/pasted directly from the email sent from Stardock. This is happening when I try to activate Icon Packager too.