From the initial program I save the other program in data memory and I want to jump and execute this second program. How can I do it? Thanks!!!
If that truly is data memory you wrote the code to, then you can't. The 8051's architecture separates code and data memory quite strictly. You can change that by board design (combine code and data memory chip select lines), but nothing in your post indicated you did that. If you did, see the other reply for how to access it.