Dependency resolution for libzypp?

I try to update my openSUSE system from 11.3 to 11.4. But I stumble on the following message.

Sonne:~ # zypper up zypper
...
Problem: zypper-1.5.3-3.2.x86_64 requires libzypp.so.810()(64bit), but this requirement cannot be provided
  uninstallable providers: libzypp-8.12.1-3.3.x86_64[Haupt-Repository_(Open_Source_Software)_11.4]
...

I wonder why the library is not found at the moment.