You might remember that I had switched to Jaunty to give it a test drive. Well, since yesterday I was having this problem with apt. It was throwing a segmentation fault whenever I tried to work with its repos (upgrade would seg fault, and dist-upgrade, and the same for install). In other words.... a broken apt = an un-upgradable system. Not good. That's not something I wanted to face at all. Having X not start once in a while is something... but having a broken package manager is a whole different story.
After submitting the bug to launchpad and spending a little time at #ubuntu+1 one guy there (Thanks, IntuitiveNipple) noticed that one of the files that apt handles appeared to be broken (/var/cache/apt/pkgcache.bin). I removed the file, but the file stayed there on the FS (go figure!). After some attempts at it, I was able to remove the file. But then I tried to update again... and BOOM! SEGFAULT. It's not going to give itself away so easily.
So.. after about 24 hours I'm stuck with no clue of what to do. I even had the crazy thought of reinstalling kubuntu from scratch (hell, I hated that thought.... made me think of my long forgotten days of formatting every 6 months to reinstall güindous). But I did a simple test instead: Switched my repos to use the venezuelan repositories instead of the colombian ones:
$ sudo su
# cd /etc/apt/
# sed 's/co\./ve\./' sources.list > sources.list.ve
# mv sources.list sources.list.co
# mv sources.list.ve sources.list
And voilà, apt is back on track. So the problem was the repos for colombia after all. Hope they solve it soon.... and why didn't apt complain about a discrepancy or something instead of exploding? Weird.