vcov function with lme object

[Achaz Graf Von Hardenberg <achaz.von.hardenberg@usherbrooke.ca>]

Hi,
I would like to obtain the variance-covariance matrix for an lme object and
terefore tried the following:

>library(MASS)
>x<- vcov(myobject.lme)

however, I get the following error message:

Error in UseMethod("vcov"): no specific or default method found

What am I doing wrong?

thanks!

Achaz von Hardenberg

Département de biologie,
Université de Sherbrooke,
Sherbrooke (QC)
J1K2R1 Canada