Problem with up2date -> rpm was unable to load a header

Hi there, 

we have a problem when using up2date. The error is pretty simple: 


# up2date -l 

Fetching Obsoletes list for channel: rhel-i386-as-3...

Fetching rpm headers...
rpm was unable to load a header
Segmentation Fault


Not all up2date operations yield this error, but many do (up2date -l,
up2date -u, up2date -d...). For example, up2date --get, up2date
--showall, up2date --register, work with no problem 


/var/log/up2date does not output any error message:


[Thu Oct 25 12:22:07 2007] up2date logging into up2date server
[Thu Oct 25 12:22:08 2007] up2date successfully retrieved authentication
token from up2date server
[Thu Oct 25 12:22:08 2007] up2date availablePackageList from network


i've updated the up2date package manually, but the error persists. 

I give some info about the system just in case it may be useful:


Red Hat Enterprise Linux AS release 3 (Taroon Update 8)
Linux 2.4.21-47.0.1.ELsmp #1 SMP Fri Oct 13 17:56:20 EDT 2006 i686 i686
i386 GNU/Linux

# rpm -qa | grep up2date

up2date-gnome-4.5.5-8.el3
up2date-4.5.5-8.el3

# rpm -qa | grep rpm

redhat-java-rpm-scripts-1.0.2-2
rpmdb-redhat-3-0.20060712
rpm-4.2.3-30_nonptl
rpm-build-4.2.3-30_nonptl
redhat-rpm-config-8.0.28-4
rpm-python-4.2.3-30_nonptl
rpm-devel-4.2.3-30_nonptl
rpm-libs-4.2.3-30_nonptl


I don't really know how to go ahead with it. Anyone could give me a tip
or something? 

Thanks in advance..

Diego