I will try that later today when I have time.
As for your instructions - how would someone know to do what you suggest?
What is going on behind the scene when I do select from the combo for Shopname? Something is certainly being processed.
Please see this regarding table structure
http://access.mvps.org/access/lookupfields.htm
I have looked at your database briefly and do not know what is causing the issue. I restricted the Company and Sales to just BestBuy. When I go to Next Sale 3 times I would expect to get the error on the 4th try. But it did not happen, I had to go to the 5th next Sale to get the error message.
What I don't understand is you do not get a "no current record" if you keep clicking on the Next Company. But I never got an error.
I noticed you are using table lookups (lookups at the table level), which are considered poor practice. I did not try to remove these. They might be the root of the issue, but may not be related to the issue.
Perhaps someone elsewill review your set up and have an answer.