Fedora-12 yum update dependency problems

[KC8LDO]

I just did my normal yum update routine and found several problems flagged 
as below:

[root at Fedora-12 Desktop]# yum update
Loaded plugins: presto, refresh-packagekit
Setting up Update Process
Resolving Dependencies
--> Running transaction check
---> Package firefox.i686 0:3.5.12-1.fc12 set to be updated
---> Package xulrunner.i686 0:1.9.1.12-1.fc12 set to be updated
---> Package xulrunner-devel.i686 0:1.9.1.12-1.fc12 set to be updated
--> Processing Dependency: pkgconfig(nspr) >= 4.8.6 for package: 
xulrunner-devel-1.9.1.12-1.fc12.i686
--> Finished Dependency Resolution
Error: Package: xulrunner-devel-1.9.1.12-1.fc12.i686 (updates)
           Requires: pkgconfig(nspr) >= 4.8.6
           Installed: nspr-devel-4.8.4-2.fc12.i686 (@updates)
               pkgconfig(nspr) = 4.8.4
           Available: nspr-devel-4.8.2-1.fc12.i686 (fedora)
               pkgconfig(nspr) = 4.8.2
 You could try using --skip-broken to work around the problem
** Found 1 pre-existing rpmdb problem(s), 'yum check' output follows:
tigervnc-server-1.0.1-3.fc12.i686 is a duplicate with 
tigervnc-server-1.0.0-3.fc12.i686
[root at Fedora-12 Desktop]#

Doing a "yum clean all" and "rpm --rebuilddb" did not fix the rpm database 
problem either.

Regards;

Leland C. Scott
KC8LDO

"Expecting the world to treat you fairly
because you are a good person is like
expecting the bull not to charge you
because you are a vegetarian."

Rabbi Harold Kushner