We were running into the same error and the problem has subsided after we made two changes. We are an SDE in an oracle database. I'm not a DB guy but my understanding was that traffic for the DB was running thru 2 nodes. When the load balancer shifted traffic from one node to another all of our edits were getting dropped and we getting that error message. We shifted our traffic to go to only one node, and that was the first change we made. The second was while every user had insert, delete and create priviledges on the feature class, there was still a group setting that user needed to have insert, delete and create priviledges on. Since we made these changes a few weeks ago the problem has not reared it ugly head since. Fingers are still crossed though, good luck!