[R] No CHM file

[Rebecca Sela]

I just built a package in R (version 2.1.1 on a Linux machine) and then moved it to my computer (R version 2.8.1 on a Windows machine).  When I loaded the package and tried to open help for one of the commands, I got the following warning:

Warning message:
In print.help_files_with_topic("F:/R/R-2.8.1/library/REEMtree/chm/RMSE") :
  No CHM help for 'RMSE' in package 'REEMtree' is available:
the CHM file for the package is missing

The resulting Help shows up as a window within R, instead of as the usual HTML help file.

Is this occurring because the package was built under an older version of R?  Or is there some other way to ensure that the Help files show up properly?

Thanks in advance.

Rebecca