partitioning - Unable to copy/paste partition with GParted

I have two identically sized partitions on my laptop's hard-drive (A and B we'll call them) so that when I'm ready to upgrade to a new major release of my OS on A, I can copy A to B for backup purposes, upgrade A and run on A from there. If something goes wrong, I copy B back to A and start over.

Problem is, I'm unable to use GParted to copy partitions anymore. I select my source partition in GParted and hit the Copy button and all seems good. The problem is, GParted will not let me select Paste no matter what I do. Both partitions are unmounted, and I've tried deleting the destination partition first and then selecting it, but Paste is still disabled.

I tried using parted (instead of GParted), and get the following:

(parted) cp /dev/sda 2 1
Error: File system has an incompatible feature enabled.  Compatible features are has_journal, dir_index, filetype, sparse_super and large_file.  Use tune2fs or debugfs to remove features.

I'm using a GParted live CD that has parted v1.8.8 and GParted v0.4.3.

Just for giggles, I downloaded the newest GParted live CD and had the exact same problem. However, there I was unable to run parted because GParted no longer defaults to the root user when you start a console, and I don't know the root password. Nice. I'll deal with that later.

So, what am I doing wrong?

According to GParted:

    /dev/sda1    ext3    48.35GiB
    /dev/sda2    ext3    48.35GiB
    unallocated          7.38MiB
    /dev/sda3    swap    5.74GiB
    /dev/sda4    extended
      /dev/sda5  ext3    46.61GiB

How can I copy sda2 to sda1 here?