If you install, you should uninstall via the approved way - through Control Panel add/remove in XP or Programs and Features in Vista, deleting the Folder does not get rid of Registry entries or files added to other areas, if you installed using Impulse uninstalling via that is Ok as well. The best thing to do is to re-install then uninstall properly or else try a rollback to time prior to your deletion using system restore.

Your earlier attempt to delete folders may have caused issues.

Does DeskScapes show as installed?  If not, you've corrupted something and you may have to install through Impulse to restore connections to the file system before you uninstall.

The solution is to reinstall the software through Impulse, uninstall it through Impulse (after you reboot) and then uninstall via control panel's add/delete programs.