[Spacewalk-list] Error on scheduled package install

[Tom Brown]

Hi

Trying to update a client from 5.2 to 5.2 with the latest updates -

I have subscribed this box to the channel and i see updates available so 
i select all the available updates and schedule the install.

The install fails and i see this

2/26/09 3:00:13 PM GMT Error while executing packages action: Public key 
for openldap-2.3.27-8.el5_2.4.x86_64.rpm is not installed [[6]]

Does anyone know how i can install these keys into spacewalk to allow me 
to proceed?

thanks