Handling errors in the payroll bridge application

Clients email the company their payroll files, and the columns on the payroll indicate Regular Hours, Overtime, Vacation, and so forth. To make the bridge application work, I and the other developer map the program that assigns payroll items based on this layout. It only works, however, when the layout is consistent. Whenever a client changes it by adding or deleting a column, the program generates an error.

One thing I have found so helpful in resolving errors is the Error Handler function. I use the Err object in Visual Basic, but I also add additional information such as the module name and procedure name where the error occurred. The user gets a message box, which is helpful for them, but I also wrote the program to create a log file with the same information so that I can go back and see errors that have occurred.