Most likely, this is happening because there's a file in the Library that is corrupt. So, go to Documents>Craft Edge>My Designs and temporarily move all of the files somewhere outside of that folder. Then do the same for Documents>Craft Edge>My Projects. Once those folders are empty, then try reopening SCAL. If it works, then it's one of the recent files you added.
If you still can't open SCAL after emptying those two folders, then please start a support ticket using this link:
http://www.craftedge.com/support/support_form.php