BTW, I found another set of curves in your file that has 4 unconventional closed curves, and after deleting those curves you can also use NetworkSrf to create the surface,
@Willy_Werkel you have some curves in that set that are joined to copies of themselves, making them closed curves, which will not work. Before you create any surfaces, use
SelClosedCrv
to locate the closed versions of the radial curves. Explode, SelDup, Delete. Then you can loft the remaining ones.