More and more yum dependency problems

[Harald Grossauer]

Running "yum update" for the first time in almost four weeks, I get the
following errors:

Error: Missing Dependency: gcc = 4.0.0 is needed by package libtool
Error: Missing Dependency: openoffice.org-core = 1:1.9.104-2 is needed
by package openoffice.org-pyuno
Error: Unable to satisfy dependencies
Error: Package mozilla needs mozilla-nss = 37:1.7.8-2, this is not
available.
Error: Package mozilla needs mozilla-nspr = 37:1.7.8-2, this is not
available.
Error: Package libtool needs gcc = 4.0.0, this is not available.
Error: Package openoffice.org-pyuno needs openoffice.org-core =
1:1.9.104-2, this is not available.

Any ideas what is going on here?