By chance can you enlighten us with exactly what it is that you're doing?
It seems like you might be attempting to install a new operating system of some kind, while you have a few already on the system in question.
Judging from the structure of your post alone, I would bet you're an Ubuntu user, and a bit new to Linux. In which case, Welcome to the community! (Please click on the links in my signature for some very helpful information).
You shouldn't need to import anything from the other filesystems during an operating system upgrade. In fact, unless you have a current backup, I would recommend against it.
If you want to be able to mount up your /home directory from another distro (such as your Fedora Core 10, or Ubuntu 8.04 installations), you will have to have detailed knowledge of your disk layout and partition/filesystem scheme.
For example, most Fedora Core and Ubuntu installations I've seen don't cut a separate filesystem for just /home, so you may need to mount up the "root" filesystem (that's "/", not "/root") in order to access your home directory.
In the future, I would recommend setting aside a separate partition for just your home directory, so that it can be shared across distributions. If you're going to just have various Linux distributions on the system in question, then you may want to format that filesystem with Ext3. It's supported by default in many Linux distributions.
For the Win; grab SlackWare 13
. After all, the saying goes;
"If you get Red Hat, you learn Red Hat.
If you get Debian, you learn Debian.
But if you want to learn Linux, you get Slackware."