While performing a typical install using the GUI installer from the 2006.1 LiveCD, I chose for Gentoo to use my existing partitions, and not resize any thing, just reformat them. Once the installation began, it ended with an error saying it couldn't resize the partitions, which is wasn't even supposed to do to begin with. This happened twice with, the only difference was that the second time the root partition was 60GB instead or 40GB. The basic setup was a Windows NTFS partition first followed by and extended partition with the Linux partitions on logical partitions with in it. This was on a SATA drive with no other previous problems.
*** This bug has been marked as a duplicate of 153634 ***
*** Bug 159559 has been marked as a duplicate of this bug. ***
This bug has nothing to do with an unknown partition, thus not a duplicate of 153634.
Filing duplicate bugs with identical description is not really useful, just plain annoying. If you feel you got misunderstood and this one is not really a duplicate of Bug 153634, that basically implies that your bug description pretty much sucks. There's not a single thing implying any data loss whatsoever in comment #0.
Also, the installer creates logs for a reason; attach them when filing bugs.
Perhaps if you gave some actual details, we might be able to actually do something. What is a "typical install"? What were your existing partitions (start/end, size, type, etc.)? What was the exact error? Perhaps you could attach your installprofile.xml and install.log.failed like the error message tells you to. Reopen when you do so.
This is no longer an issue with the new partitioning in 2007.0