Package update

Hi Admins,

Fedora Core 4

I am stuck in a vicious circle trying to update libxml2. My installed 
version is 2.6.20 which I 
understand is broken and I need version 2.6.27. 

I have tried to use yum to update the package (and it's 
dependencies). 
>yum search libxml2
libxml2.i386             2.6.20-1.FC4           updates-released
libxml2.i386             2.6.20-1.FC4           installed

I figure from the output that I already have the latest version 
available from my mirror site installed.

At this point I thought I'd tried to install the 2.6.27 rpm manually 
but  there are dependency failures:

error: Failed dependencies:
        libc.so.6(GLIBC_2.4) is needed by libxml2-2.6.27-1.i386
        rtld(GNU_HASH) is needed by libxml2-2.6.27-1.i386
        libxml2 = 2.6.20 is needed by (installed) libxml2-python-
2.6.20-1.FC4.i386
        libxml2 = 2.6.20 is needed by (installed) libxml2-devel-
2.6.20-1.FC4.i386

I am using glibc.i686  2.3.6-3.

I am very nervous about trying to update glibc, especially as there 
doesn't seem to be a version available to yum so it could take care 
of the dependency.

Does anyone have any ideas about how to proceed? I know FC5 has glibc 
2.4.11+ and libxml 2.6.23 but I really want to avoid a complete OS 
upgrade.  

TIA,
Dp.