[R] reference class error

[Filippo Monari]

hi,
I'm new to reference classes but as I have experience with python I 
decided to port some of my code in this frame work.
I have the following two reference classes in separate files:

#1#
uvRndVar = setRefClass(
     Class = 'uvRndVar',
     fields = list(
         desc = 'character',
         type = 'character',
         pars = 'list',
         MAP = c('numeric'),
         post = c('numeric')
     ),
     methods = list(
         initialize = function (desc, type, pars) {
             types = c('norm', 'lnorm', 'beta', 'gamma')
             parameters = list(norm = c('mean', 'sd'), lnorm = c('mean', 
'sd'),
                 beta = c('shape1', 'shape2'), gamma = c('shape', 'rate'))
             if (!any(types == type)) {
                 stop('not correct type provided')
             } else {
                 if (length(names(pars)) == length(parameters[[type]])) {
                     for (i in 1:length(names(pars))) {
                         a = which(parameters[[type]] == names(pars)[i])
                         if (length(a)) {
                             parameters[[type]] = parameters[[type]][-a]
                         } else {
                             stop(paste('parameter', names(pars)[i], 
'not compatible with provided type'))
                         }
                     }
                     .self$desc = desc
                     .self$type = type
                     .self$pars = pars
                     .self$MAP = NaN
                     .self$post = NaN
                 } else {
                     stop('parameter list provided has wrong length')
                 }
             }
         }
     )
)


#2#
NG = setRefClass(
     Class = 'NG',
     fields = list(
         Y = 'matrix',
         X = 'matrix',
         CvFun = 'Cf',
         CfHp = 'list',
         lam = 'uvRndVar',
         lam.upd = 'logical',
         A = 'array',
         basis = 'matrix',
         Y.star = 'matrix',
         X.star = 'matrix',
         lam.star = 'numeric',
         lam.star.upd = 'logical',
         A.star = 'matrix'
     ),
     methods = list(
         initialize = function (Y, X, Cf, CfHp, lam, A, basis) {
             if (nrow(Y) != nrow(X)) {
                 stop('X and Y have different numbers of rows')
             } else if (dim(A)[1] != dim(A)[2]) {
                 stop('A is not a square matrix')
             } else if (dim(A)[1] != nrow(basis)) {
                 stop('basis matrix and precision matrix A have 
different number of rows')
             } else if (dim(A)[3] != nrow(X)) {
                 stop('dim(A)[3] != nrow(X)')
             } else if (ncol(basis) != ncol(Y)) {
                 stop('basis matrix and Y have different number of columns')
             } else {
                 CvFun$checkModel(Y, X, CfHp)
             }
             .self$q = ncol(Y)
             .self$m = nrow(X)
             .self$p = ncol(X)
             .self$n = nrow(basis)
             .self$Y = Y
             .self$X = X
             .self$CvFun = CvFun
             .self$CfHp = CfHp
             .self$lam = lam
             .self$A = A
             .self$basis = basis
         }
     )
)


the second takes an object of the first class in two of its fields. I 
load the first class and then the second with the 'source' command, but 
then I got this error which i don't understand:

Error in match(x, table, nomatch = 0L) :
   argument "type" is missing, with no default

I'm working with Ubuntu 12.04 and R 3.0.2.
Any suggestions about what is going wrong?
Thanks in advance,
Filippo