Ah, interesting -- definitely sounds like a third party program, then. We've had issues with AVAST having a false positive on some of our games before, and Kaspersky in 2011 did until they fixed their definitions. This would be the first report with Norton, but it would not surprise me since a lot of antivirus now use predictive algorithms that have some false positives (much better than missing some things on false negatives, in the main, but it can cause stuff like this).
