How long is the request running before the exception and what does the XML of your call look like?
There is not too much time before exception, far less than timeout setting.
I could not see the raw XML of request/response. I'm using the SOAP APIs coding by Visual Studio automatically, with StreamPosition of oldestCreatedAt = '2015-04-07T00:00:00Z' and latestCreatedAt = '2015-05-07T00:00:00Z', and ActivityTypeFilter.includeTypes = ['Click Link','Visit Webpage','Interesting Moment','Open Email','Email Bounced Soft','Fill Out Form','Unsubscribe Email','Click Email'].
I think the request XML is valid because it works well for most data.