Description of problem:

Something went really funny with package dependencies in
an updates set 'rpmdb-fedora-2.91-0.20040929'.  It looks
to me that the problem is not in yum but in rpm libraries.

After failed attempts to use yum I tried directly 'rpm -Fvh ...'
with a bunch of packages from that update set and ended up with:

error: Failed dependencies:
        linc >= 0.1.6 is needed by (installed) pyorbit-2.0.0-3.1
        linc = 1.0.3 is needed by (installed) linc-devel-1.0.3-6

while 'rpm -q linc' responds with 'linc-1.0.3-6' and
'rpm -q linc-devel' with 'linc-devel-1.0.3-6'.  The error appears
to trip yum.

It seems that the real culprit is ORBit2, though, but why it
triggers this problem is far from clear to me.  Still, when other
packages are got updated then ORBit2, and ORBit2-devel, could be 
updated as well but only then.

Originally yum was unhappy both with 2.1.3-1 version and also
after an update to yum-2.1.4-1; but as I said, this does not
look really as a yum fault.  I also tried that on a local repository
generated with 'createrepo' on a directory with copies of all
needed rpms.  Regardless if 'linc' packages were present or not
during a createrepo run results were exactly the same - i.e. yum
was bailing out complaining about needed 'linc'.