How to do a rollback of an rpm that was installed with up2date

[Steve Buehler]

I have my up2date set to allow-rollbacks.  I am running RHEL ES 
4.  On June 20th I did an up2date -u and one of the updates screwed 
some programs up that my customer had written.  If I do an "up2date 
--list-rollbacks", I get the following (most of them I have deleted 
so that it will be a shorter list.
install time: Mon Jun 20 08:22:09 2005   tid:1119273729
                 [-] initscripts-7.93.11.EL-1.centos4:
                 [-] java-1.4.2-gcj-compat-1.4.2.0-26jpp:
                 [-] kernel-utils-2.4-13.1.48:1
                 [+] libtool-libs-1.5.6-4.EL4.1:
                 [+] java-1.4.2-gcj-compat-1.4.2.0-27jpp:
                 [+] gnome-session-2.8.0-5.centos4:

The only one that I want to rollback is the java-1.4.2-gcj-compat 
one.  An "rpm -qa|grep java" tells me that I am running:
java-1.4.2-gcj-compat-1.4.2.0-27jpp
I can't seem to find the command to do the rollback.  Any help would 
be appreciated.  I tried going to the /var/spool/repackage directory 
and running:
rpm -Uvh --oldpackage java-1.4.2-gcj-compat-1.4.2.0-26jpp.noarch.rpm
but that gave me the following error:
error: java-1.4.2-gcj-compat-1.4.2.0-26jpp.noarch.rpm: V3 DSA 
signature: BAD, key ID 443e1821
error: java-1.4.2-gcj-compat-1.4.2.0-26jpp.noarch.rpm cannot be installed


Thanks
Steve