users breaking threads

[محروم.كوم]

one of my users has decided to "break" threads by posting something in them, its apparently too big to handle and when you try to access the page he posted on, a white page comes up. all other pages in the threads work. when i try to view that person's recent posts i get a blank page. how can i view/delete his offending posts? __DEFINE_LIKE_SHARE__