@MartinF: I trace the error to wget, for some reason it can't download from the link you posted, but in firefox I click it and it download right away
I even tried the direct link http://sourceforge.net/project/downloading.php?groupname=btanks&filename=btanks-0.8.7686.tar.bz2&use_mirror=ufpr with wget but it failed again

Are you online when you do that? You should be, so that the source tarball is downloaded. Or download it manually and put it in the same dir.

yes Im online, I previously said that in firefox I can download it, but I can't download it with wget
I tried putting the zenbuild in the source directory but buildpkg insist in trying (and failing) to download it again

mmmm, apparently buildpkg (or wget) can't download anything listed in the zenbuild
I put the zenbuild in the source directory and whenever I ran buildpkg it complained that wget couldn't download something
eventually it builded the package but it complained about all the missing things it didn't download

Very strange, you can get all the source files manually, except the battle tanks source tarball, from here: http://pnboy.pinguix.com/gapan/btanks/

The link is OK
wget might take some time to start downloading the file because sourceforge.net assigns you a mirror depending of your location. This sometimes takes a minute or so, others it's is assigned right away. It may depend of the site traffic also.