We haven't seen any Rockaway specific reports of behavior like this, or at least it's not ringing a bell for me. Are you only saving a single Opportunity model, or is this a multi-model save? I'd start by inspecting each model in the save to see if it needs a Name field specified (i.e. nothing with an auto number Name field), and if it doesn't have one, why not? How is that field supposed to get populated on this page?