FocaaBR, you're welcome :-)
lawliet, okay, sed is the same as mine. I've looked into the code in that image.bbclass and I think it actually may be some unexpected output from one of the commands they run there, which causes such effect. Let's see what we can find further. Do you have "fc-cache" utility, what does "fc-cache --version" return?
As far as patching is concerned - I've just used Ubuntu's built-in autoupdater, it pops us by itself (by default) when there are updated packages to install.
The Yocto sources should be ok - the setup.sh script you use to setup everything initially downloads proper (specific) versions of necessary additional repos. During the build bitbake also downloads package sources it builds if the cache doesn't have it or if it's corrupted, so I wouldn't worry about that much. In the worst case you can run "bitbake -c cleansstate image-full", which would purge all the caches and start everything from scratch.
The prerequisites are listed in the BSP Build Guide, though in several places. IIRC I haven't installed anything beyond these packages, I've listed them a couple of posts earlier in this thread.