You could patch apt-show-versions with this diff, then the message is gone.
--- apt-show-versions.orig 2014-08-18 14:38:10.791635143 +0200
+++ apt-show-versions 2014-08-18 14:36:10.753920168 +0200
@@ -261,7 +261,7 @@
or $cache_file_corrupt) {
my ($href, $release) = &parse_file ($_);
foreach my $pkg (keys %$href) {
- foreach my $arch (keys $href->{$pkg}) {
+ foreach my $arch (keys %{ $href->{$pkg} }) {
$apackages->{$pkg}{$arch}{$release} = $href->{$pkg}{$arch};
}
}
@@ -356,7 +356,7 @@
printf("%s not installed (not available)\n", $pkgname);
}
} else {
- foreach my $arch ($archname or sort keys $pkgs->{$pkgname}) {
+ foreach my $arch ($archname or sort keys % {$pkgs->{$pkgname}}) {
print_package_internal($pkgname, $arch);
}
}