do you see "no updates available" in the bottom? or you see there "checking for updates..." constantly? if ZModeler can't reach updates sever, it is impossible to reach licensing server too. Start with administrative privileges.
re-assign password to your platform in account on "My computers" page, try something simple like 555666. then update password in zmodeler on it's "Account Setup" page too. then close zmodeler, restart after 2-3 seconds and open License Information window.