Mine looks like this:

TraceCall: calling the real execution over the webresponse Returned contenttype is: text/html from URI : http://www.google.com/calendar/feeds/myaddr...@gma...@ Returned statuscode is: Found302 throwing for redirect Got into exception handling for base.execute Got a redirect. http://www.google.com/calendar/feeds/nick.chadw......@nichesolutions.co.uk/private/full Using auth token: ***************** TraceCall: calling the real execution over the webresponse Returned contenttype is: application/atom+xml; charset=UTF-8 from URI : http://www.google.com/calendar/feeds/myaddr...@gma...@ Returned statuscode is: Created201

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It is very strange that you can query feeds but cannot insert a new item, as they both use the same redirect/token method.

The fact that you are seeing a "first chance exception" is interesting. That normally means that .NET is alerting you to an exception BEFORE it checks to see whether that exception is handled by an enclosing try-catch. Presumably you are running your app within the IDE - you will get the usual dialog with continue/debug/etc. buttons. Just try clicking "continue", and see if that makes any difference. (Although I would expect the same behaviour querying a feed...)