SuSE update: RPM has invalid signature (?)

Dear All, Have just installed SuSE 9.2 with a network install (ftp.mirrorservice.org), and want to apply patches. Each time I run YOU it starts to download each patch and then fails. Under the details I see that the "RPM has invalid signature". How can I fix this? It's driving me absolutely nuts! Cheers, Jon. -- Jonathan Brooks (Ph.D.) Research Assistant PaIN Group, Department of Human Anatomy & Genetics University of Oxford, South Parks Road, Oxford, OX1 3QX tel: 01865 272156 fax: 01865 282675