This is not an easy one. It's not your fault and you can't prevent connection resets, unless it's simply a case of exceeding your timeout limit. Salesforce.com connections go down for any and all reasons. The exceptions are not classed in ways that would let you differentiate error conditions at the record level vs. a collection of records vs. Salesforce.com internal errors vs. your internet connection going down.

We have spent three years refining the retry-restart logic in Relational Junction so that we can gaurantee delivery of all data, not create duplicates, auto-connect for up to 20 minutes, auto-retry all failures, and restart as close as possible to the point of failure. There are lessons in this that expose the myth of how easy it is to develop a home-grown solution, despite the excellent quality of the API functionality and documentation. The devil's in the details. Our major sales competition is the do-it-yourselfers who don't realize the complexity of proper error handling; anybody can write code that assumes everything's all right.

If you would like to talk to me directly, send an email to rick.banister@sesamesoftware.com with your phone and a good time to talk.