Probably you are working on Windows Vista or Windows se7en?
To enable proper demo operation on Vista or Windows se7en please disengage UAC - User Account Control which limits registry operations and turn the plug-in into demo expired mode or run your DAW as administrator of your system.

How to do it?

UAC - User Account Control

1) Open up Control Panel, and type in “UAC” into the search box. You’ll see a link for “Turn User Account Control (UAC) on or off”

2) On the next screen you should uncheck the box for “Use User Account Control (UAC)”, and then click on the OK button.

3) You’ll need to reboot your computer before the changes take effect, but you should be all done with annoying prompts.

Note: Disabling UAC will lead to a less secure system, so be warned.


How to activate the Administrator Account

You can do it thru User Account Control

1. Go to your Start menu and right-click on the “My Computer” icon.

2. Choosing “Manage” from the list will prompt a User Account Control (UAC).

3. When you are done, the “Computer Management console” will appear. Expand the “Local Users and Groups” option with the use of the arrow next to it and choose “Users” folder.

4. You can now select the “Administrator Account” and go to the “Actions” panel to open “More Actions”.

5. Choose “Properties” to open the “Administrator Properties” dialog box and uncheck the option labeled “Account is Disabled”.

6. When done, click “OK” to confirm changes.

7. The Administrator account should now be present on your log in screen.


More info about UAC you can find at
http://en.wikipedia.org/wiki/User_Account_Control