Sometimes when I click the Show 100 Messages link on threads I get the "Oops - damn, something went wrong" page. It only seems to happen on certain threads - this is the one I just tried: www.mumsnet.com/Talk/am_i_being_unreasonable/3954364-What-s-most-OTT-response-you-ve-ever-seen-on-a-thread
On other threads it works no problem.