>>No admin interface, so if they want to change prices they have to enter SQL queries themselves. Not ideal.
well building an admin interface is expensive. however you should at least write a stored procedure on the sqlserver which you can call to change prices, it's always a risk writing out new queries to run against the database each time you want to update it (incase there is an error in the query that causes an irreversible change.
Then, when I re-uploaded the _backup_ files, the script exited immediately with a error message.
Check that it is being uploaded in the correct format (binary/ASCII) in your FTP client. It might be that the FTP program you use either doesn't recognise .aspx, perhaps only recognising .asp extensions.