Why did you not look at "line 193" of "/usr/share­/perl5/JSO­N/RPC/Clie­nt.pm" ? Wouldn't that be the first logical thing to do?

I went to search.cpan.org and searched for that module, JSON::RPC::Client, clicked the "Source" link, pasted that into my editor, and jumped to line 193.

I don't know if this is the same version of the module that you are using, but getting that error at that line appears to make sense:

sub new {
    my ($class, $obj, $json) = @_;
    my $content = ( $json || JSON->new->utf8 )->decode( $obj->content 
+);

    my $self = bless {
        jsontext  => $obj->content,
        content   => $content,
    }, $class;

    $content->{error} ? $self->is_success(0) : $self->is_success(1);
    # ^line 193
    $content->{version} ? $self->version(1.1) : $self->version(0) ;

    $self;
}
[download]

I'll give you a chance to diagnose the problem from there. It doesn't appear particularly difficult to me.