I\'ve managed to get the Rcpp.package.skeleton to INSTALL in Windows by the following commands at the R prompt -
Rcpp.package.skeleton
Rcpp.package.skeleton(\"mypackage\"
FWIW, I just got a similar error while retrofitting an existing R-only package with Rcpp, and the problem was a missing useDynLib(mypackage) in NAMESPACE.
useDynLib(mypackage)
NAMESPACE