You would have to start by reproducing the error. There has to be a set of steps that cause the problem. A certain path the user goes through. Maybe failing validation first, or going through a different page that causes the problem.
Once you can re-create the error, then I can easily debug and fix it. Without that I'd just be blindly trying different things to see the problem in the first place, and without complete knowledge about how your site works and all of the options, I might overlook possible steps and not find it.
If you want to call and set up a premier support ticket I can do screen sharing with you and we can walk through all of the possible paths a user might follow to get the insert into the database. Then we can see which one causes the problem and then we can track why it occurs and get it fixed.