There is no way to write to an external file with the stock FPSC, or save the variables from level to level.
Have the user manual enter a code they received from the previous level.
So each level could actually give different codes depending on the users actions in the level so they could be sent to any other level.
Then when the exe ends and your program is returned control the user would input the code and then the program would run the proper exe.
No, I'm not a DBPro expert, and I have not made any menus for FPSC with DBP, so its just a thought.