The relevant log lines are these:
Notice the insane number of vertices associated with that rigged mesh... Not a surprise that it quickly exhausts the available memory.
This is an invalid rigged mesh, probably a crasher object, and it's not a viewer bug (even if there may be a way to detect and take action against such crasher objects; I'll have a look at an auto-derender possibility). Now, it would help identifying which mesh is causing that issue (InWorldz admins may help you doing it).
One question however (since there are two paths in the code where the out of memory condition happens): do you have the mesh deformer feature enabled or not (if enabled, it would explain why other viewers are not affected since they don't have it) ?
EDIT: I found a way to auto-derender such bogus objects and to pin-point them in the log (by their UUID and the name of the avatar wearing them). I will PM you the link to a test viewer including that code (compiling it right as I'm writing these lines).