I think the first problem is a memory issue.   Poser isn't very clever at handling memory, especially at discarding memory which it no longer needs, so it can acquire loads of memory during a render and then try to acquire even more, when you attempt to switch back to Preview, rather than making full use of the memory it already has.   Sometimes, the full set of textures will eventually load, but I think it is safest to shut down Poser and start again.   For that reason (and quite a few others), it's always safest to save the file before doing any kind of render, in my opinion.  

As for the EW problem, the blue top certainly doesn't look remotely like the Rhiannon version.    Is it possible that your runtime contains a mixture of two Elsas:  Elsa Wylde and, perhaps, some freebie called Elsa?   I can't see how the EW top could ever end up looking like the blue image, otherwise.   The EW top does load OK for me (V4.2, PoserPro, same version of Windows).