You must recompile Visual FoxPro 3.0 program (.prg), form (.scx), query (.qpr), menu (.mpr), report (.frx), and database (.dbc), and class library (.vcx) files to run them in Visual FoxPro version 5.0 or later.
To run Visual FoxPro 3.0 applications in Visual FoxPro version 5.0 or later
You must convert Visual FoxPro 3.0 projects to run them in Visual FoxPro version 5.0 or later. For details, see Converting Visual FoxPro 3.0 Files.