R help - Feb 2009 - Error message when executing summary() with dataset diamonds in ggplot2

Hi:  I am experiencing a problem with dataset diamonds in ggplot2.  When
trying execute the summary(diamonds) statement, the following error message
is displayed:
Error in summary(diamonds) : 	
Cannot open file
'C:/Users/James/R_Pgms/R/R-2.8.1/library/ggplot2/data/Rdata.rdb': No
such
file or directory

Can you please advise me?

A complete history of commands leading up to this problem is as follows.  I
have also included in this history a set of parallel statements (involving a
different dataset, Davis, in a different package, car) for which the summary
command executed OK.  My first three commands were as
follows:
> library(car)
> library(ggplot2)
> search()
The displayed results of the search command confirmed that both packages
were now in the search path.  

The next three commands were as follows:
> data(Davis)
> data(diamonds)
> ls()
The displayed results of the list command confirmed that both datasets were
in the workspace.  

Next, the following  statement provided the expected dataframe
summary
> summary(Davis)
However, a similar statement for the dataframe diamonds resulted in the
error message described above.

I am running on a PC with Vista and SP1  The sessionInfo() command displayed
the following:
R version 2.8.1 (2008-12-22) 
i386-pc-mingw32 

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

attached base packages:
[1] grid      stats     graphics  grDevices datasets  utils     methods  
[8] base     

other attached packages:
[1] ggplot2_0.8.1   reshape_0.8.2   plyr_0.1.4      proto_0.3-8    
[5] car_1.2-11      rcom_2.0-4      rscproxy_1.0-12

loaded via a namespace (and not attached):
[1] tools_2.8.1