One of the teething problems in Lion is that the operating system does not work well with some third-party network attached storage (NAS) solutions. As we await OS X 10.7.1 update to fix those problems, manufacturers like Western Digital are taking this matter into their own hands. Western Digital, for example, yesterday released a firmware update for the My Book Live series, making it compatible with OS X Lion and Time Machine.
Western Digital uses Netatalk, an open source AFP fileserver. When Apple made changes to AFP function in Lion, it caused major woes as Netatalk had to be updated. According to release notes (PDF document), the software can be downloaded manually or automatically, by accessing the drive via Bonjour or using the WD QuickView app on your Mac.