Just a guess.
Have you load lme4 before you print the object? If yes, it may be
caused by the change of representation of "mer" class.
2009/4/23 Robert Zimbardo <robertzimbardo at
gmail.com>:> 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
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
HUANG Ronggui, Wincent
PhD Candidate
Dept of Public and Social Administration
City University of Hong Kong
Home page: http://asrr.r-forge.r-project.org/rghuang.html