It's a brave new world...
Try HTML, ASP.NET, C#.NET, with SQL Server backend. Start real fresh. This will control implementation issues with VFP if you are using the usual APP or EXE at the client. You will also be in a prime position for future growth of the application; after all if it is developed for the NET, you can have a thousand users.
By using a new product, you will keep yourself more marketable as well.
I look at it this way. You are very lucky. You have an opportunity to learn and build at the same time. If I was given the same opportunity, I would choose a new language and toolset to learn.
(VFP Users: That doesn't mean I would abandon my roots. Knowledge is Gold. Knowledge can not be taken away from you either.)