[R] Failing to print mer object in an RData image

[Robert Zimbardo]

Hi all

I have problems in accessing a mer object called model.01 from a
workspace that was created with R 2.8.1 and saved with save into an
.RData file (on Windows XP or Ubuntu 8.10, don't remember anymore).
Now I want to open it in R 2.9.0 on Ubuntu 8.10. I use

# load workspace
load("name.RData")

which seems to work:

ls() # all objects in there
[1] "all"          "all.dd"       "model.01"     "model.sorter"

It also recognizes the class of model.01:

> class(model.01)
[1] "mer"
attr(,"package")
[1] "lme4"

But when I want to print it or look at its structure:

print(model.01)
Error in slot(value, what) :
  no slot of name "Xst" for this object of class "mer"

> str(model.01)
Error in FUN(c("env", "nlmodel", "frame", "call", "flist", "X", "Xst",  :
  no slot of name "Xst" for this object of class "mer"

Any idea what to do?

> R.version
platform       i486-pc-linux-gnu
arch           i486
os             linux-gnu
system         i486, linux-gnu
status
major          2
minor          9.0
year           2009
month          04
day            17
svn rev        48333
language       R
version.string R version 2.9.0 (2009-04-17)

> library(help=lme4)
Package:       lme4
Version:       0.999375-28
Date:          2008-12-13

Thanks,
RZ