We have had many many problems with service packs and clusters. We manually apply the service pack to each node. There is a known issue with service packs files don't get copied over to the second node at all. HP support should have articles on this big time. If you do a search you will see what I went through last year. We currently run SP2 with all the hot fixes. There is a DTS bug with SP3 that keeps us from upgrading.

Wes