Sorry about the delay in the response (I didn't forget about you!). I've just been trying to reproduce it on my end and have yet to succeed.
Are you having any problems with any of the other samples in the SDK or is it just this one?
If it's just this one, then I'd try changing the chunk_size varaible in the sample and comment out the part where the chunk_size is incremented. That will force a request size of 1 virtual per request. If this still causes a problem, then you will have to open a case with support to get a developer working on it.
-Joe