Fedora :: Root Logical Volume Ran Out Of Space?

My computer: (Lenovo T61 Thinkpad, running fc11 for about 2 and half months). Apparently I when I made my partitions I didn't leave quite enough room in my root directory, because I just completely ran out. Here is how my hard drive is partitioned:

1 physical volume group (sda)
4 logical volumes (home, root, swap, var)

The root had about 15 gigs on it, which just filled up. When I restarted to see if that would help, when it rebooted it went fine up to the log-in screen. Instead of the usual fedora blue background, it was black except for the log-in window, which looked very low-res. A little pop-up kept coming up saying the GNOME power configuration settings failed to load or something. When I logged in, the whole screen was black except for the mouse, and I could get no response. I have plenty of space left in home, so I rebooted to rescue mode using the first fedora installation disk, and tried the following command:

Code:

lvreduce -L90G /dev/mapper/DRIVE

which only returned:

Code:

lvreduce: relocation error: lvreduce: symbol dm_tree_node_size_changed, version Base not defined in file libdevmapper.so.1.02
So I couldn't reduce the size of home, and thus couldn't increase the size of root.

IN SUMMARY:

a) the lack of memory in root the probable cause for my computer not working

b) there a good way to reduce home and increase root while running this live disk

Note: When I am looking at it now in the logical volume manager, it says that on the whole physical volume there is only 400MB free. However, when I last looked (about 30 mins before I started having problems) it said there were about 100 Gb free.

Edit: Nevermind. I did some more research and it turned out to be more of a gnome power manager thing rather than a memory space thing, although I'm certainly going to increase my root memory now.