>Greetings Nigel
>>
>>Try changing to specify SHARED too. Be a good idea to always specify this (I find it makes life so much easier).
>
>This was the suggestion I tried last and almost rejected out of hand. Why? Because its a standalone app and why the hell should I need to share files? Godnose. But this is the one that worked!

You should find that the help file explaines that the SHARED clause has nothing to do with whether the app is standalone and everything to do with overriding SET EXCLUSIVE ON. IOW, it's relevant, too, in one instance of an app that might open a table more than once.