Thanks you for your question. I think some problem in the product item of your site (maybe the configurable product not have child option products). Please try to debug the error in the file “var/log/exception.log” and “var/log/system.log” to see detail of the problem.
If there files are larger size, you can delete them then run the website again, the magento system will generate the error in there files again. Please give me there log files if you can not find problem detail at here.
Answer for Pencil Theme Homepage Default template shortcode error.