The value that is being referenced here looks to be the session id, this would normally also be the id for the order you are storing. Any tables that you are using to store info should have a primary key column, it is standard to have an auto incrementing id column for this.
Do you have the latest eCart installed? As of the time of this post it is version 4.5.2. This reminds me of an earlier issue in eCart that should be cleared up in the latest release. If you can please post back with a copy of your confirm page minus any of the sensitive details.