Call a form from html link

Hello…
I need call a form from a link generated in a blank application.
i write:

$string_link = sc_make_link (‘form_dbo_Articulos’,Cod_Articulo=$CodArt);

The app name, and the parameter value, are correct.
But when run, the fomr is open in blank (not retrieve the record to edit).

Some help?
Thanks!!!