At this stage, I think we can say that your system has been deeply harmed... You have a chance to repair your system, however. At least I hope. Note that, as zypper is a really central library on SUSE systems, it may not work... Note also that I use an openSUSE, not a SLES, but things should be quite similar...
What you can try is to reinstall the libzypp library (or zypper, but it should be libzypp. At least, I hope). Get it manually from the repository you use ordinary... and hope you won't have a version problem later...
Once it's done, try to install it using directly rpm
. Force the installation if needed. If rpm is not broken, it may work... If it does, make your update again, in order to be sure to use a coherent system.
Good luck, I hope it will help you...