Disk recognized as source but not as destination

I am using Acronis 2009 and 2011 Home edition boot media and am having an issue with backup mode. I have two SATA drives in an HP desktop which are connected to the internal bus (not USB....). I want to create a backup imagine of the first drive and write it to the second drive. The first drive has 4 partitions (/boot /opt swap and /) and the second has only one (an ext3 partition). This is a Linux system and these partitions are not LVM. When I boot to the Acronis disk, and go to backup computer menu, I see both disks available as source. I choose disk 1 and then for target, I browse but only see C:, D:, and E: which correspond the three non-swap partitions on disk 1. There is no disk 2 partition.

I have another box that is very similar (different linux release level, etc) with two SATA drives and Acronis sees the second drive as a target possibility.

Any help appreciated.

John