[R] building package

[las65 at buffalo.edu]

I have built a package that I would like to submit to the CRAN. When I perform a R CMD 
check I get the following warning: 
* checking Rd cross-references ... WARNING
Error in .find.package(package, lib.loc) : 
  there is no package called 'foreign'
Calls: <Anonymous> -> lapply -> FUN -> .find.package
Execution halted

I believe this has to do with the fact I use mapply function utilizing internal 
functions I have within the package? Am I wrong in this assumption? How would I remedy 
this in order to get rid of the warning? 

Any advice is appreciated. 
Thank you 
Lori