Just to confirm, the page is not compltetly loading, but being cut off?
It sounds like you have a PHP error / MEMORY limit issue going on which would explain why the wp object doesn’t exist. The wp object is a JS object added by WP – most likely in the footer scripts. If the footer is never rendered, the perhaps your browser is firing the document.ready action without realizing the page is broken!
Can other confirm this is the same issue?