>We have a large application running, written in FoxPro2.6. That means, there are about 200 screens and as many reports, which are to be upgraded all of them, if we would decide to upgrade to VFP 6.0.
>However, all customers are very happy with the program how it is, so why take the risk?
>Does anybody have experience with where the problems of upgrading might be, or are there general opinions about the reasons for upgrading (or not upgrading at all)?

I think you are right that if it works then there is no benefit in upgrading especially if the application is quite static. The biggest danger is that the database application will not play well with newer hardware and operating systems. The client might upgrade their entire site to Windows 2000 and your application no longer works. Then pressure would really be on then.