try out this code for adding Profile Property:
if (DotNetNuke.Entities.Profile.ProfileController.GetPropertyDefinitionByName(this.PortalId, "Level") == null)
{
DotNetNuke.Entities.Profile.ProfileController.AddPropertyDefinition(
new DotNetNuke.Entities.Profile.ProfilePropertyDefinition(this.PortalId)
{
PropertyName = "Name",
DataType = 10,
...
});
}