>After converting the project to VFP6 using the conversion wizard, the data files are not loaded in the project, and adding them as free tables do not help.

Helping what exactly?

>what is the best way to a successful conversion?


When adding tables to the project insure the 'exclude/include' status of the tables is correct. This status can be modified in the project menu. If a data file is 'included' in a project then the '.app' or '.exe' file built from the project CANNOT modify the contents of the table. The table remains 'static'.
A file is 'excluded' when a circle with a slash through it is just to the left of the file name.

HTH