>>>I may have this in a few places but not sure that would be related in that the error is happening inconsistently and from different places in the app
>>>Forgot to say in initial thread that :
>>> c:\users\fred\appdata\local\temp\MyErrorRoutine.fxp
>>>
>>>User fred is Me i.e. My development machine and there is no user fred on the site the app is deployed in
>>>Neither do I bave anything in the Config.fpw file
>>>
>>>How could the exe be throwing up a reference looking for the devlopment machine User ??
>>>

I recently fought a similar problem. In my case, the culprit was a file called with an explicit path which was compiled into the .EXE.

I suggest you use Code References or a similar tool and search the project for "c:\users\fred\appdata\local\temp\MyErrorRoutine.fxp" or parts of until you find and fix it.

Failing that, copying the .fxp from your development machine to the folder where the program is installed may fool it into working properly.

Chris.