problem with update.varComb in nlme

[Gosselin Frederic <Frederic.Gosselin@nogent.cemagref.fr>]

Dear all,

I use S+6.02 and nlme library n°3.3.1.

I have come with a problem with the function varComb used in the weights argument of a nlme model. When I use this function, I get the following error message:

Problem in update.varComb(...X.sub.i...., list(group = structure(.Data = "" 1, 1..: Object "data" not found

The complete formula in which it is used is rather tedious; here it is:

mod.vsa1.1L.R.SU.stgu_nlme(y~lien.exp(a),fixed=a~group,data="">

Does someone have an explanation for this?

Friendly,

Frédéric Gosselin
Cemagref
Domaine des Barres
45 290 Nogent-sur-Vernisson
FRANCE

Tel: 02-38-95-03-58 (from abroad: 33-2-38-95-03-58)
Fax: 02-38-95-03-44 (from abroad: 33-2-38-95-03-44)