Do not change mirrors to get SliTaz 4 packages. It WILL break SliTaz 3 and probably try to (badly) upgrade to SliTaz 4. THIS IS NOT A BUG. If your SliTaz installation breaks because you did this, it's your own fault.
Use http://pkgs.slitaz.org/ and search for the package you want. Then download the file and try installing it with tazpkg install /path/to/package.tazpkg
