What is your e: drive? OneCare can backup to CD/DVD, external USB and firewire drives,network shares, and a multitude of flash memory devices. It will *not* backup to another internal drive, nor will is currently backup to most eSATA drives as these appear as internal drives to OneCare.
What version of OneCare are you running? The 2.0 beta or 1.6 released version?
-steve