The key word here may be 'environment'. Your app running in development mode receives the VFP environment that you set up for development. Try setting up your environment with a series of set commands.
SET EXACT ON
SET EXCL OFFF
SET .....
you get the idea.

Hi Terry,
Another basic Q, if you don't mind...
What happens if I do not setup any SET command..., where does the 'environment' setup is comming from? is there a default, or the development environment ?

Thanks,
Gadi