Error on my page

I’m not actually seeing that error on the page you linked to – but this sounds like something that can happen with certain themes/plugins that for various reasons override WordPress’s global $wp_query object. That may not be the cause but it is definitely a possibility and in the first instance I’d encourage you to:

• Deactivate all other plugins
• Switch to a default, unmodified theme such as Twenty Twelve
• Check if the problem occurs under these circumstances

Thanks!