[arch-general] Cannot update yaourt and package-query

Hello, I can't update yaourt and package-query via pacman -Syu because I get an error which says the package is broken and there's a problem with the PGP signature. [1] I can ignore this package but I think it's not a good solution. What can I do? Thanks for your answers. -- Vik [1]: Original Error (in German): "Datei /var/cache/pacman/pkg/package-query-1.3-1-x86_64.pkg.tar.xz ist beschädigt (Ungültiges oder beschädigtes Paket (PGP-Signatur)). Soll die Datei entfernt werden? [J/n]"