Yeah, that makes sense. BlockUI doesn't clone the element, but it does move it to another part of the DOM and then removes it from the DOM when unblockUI is called. So the 2nd time through you were binding your yes/no events while those elements were not part of the DOM (which means jQuery can't find them and they don't get bound).
Glad you got it sorted out! Mike
Does it make sense to you ? The only thing I see would be that blockUI does clone the modal div, and that things are messed up because events are registered before this clone() or something like that.