dependent packages not loading in R on Debian

I'm having trouble loading the sde package on a clean Debian install running R 2.11.1. I've seen this behavior with some other packages, however, so I don't think it's specific to only this one package. Here's an example of the conundrum:

>install.packages("sde", lib.loc=libPath)

... installs sde, and the packages it's dependent on: zoo, fda

> library(sde,  lib=libPath)
Loading required package: fda
Error: package 'fda' could not be loaded
In addition: Warning message:
In library(pkg, character.only = TRUE, logical.return = TRUE, lib.loc = lib.loc) :
  there is no package called 'fda'

ok, that's odd. I saw fda being installed. So I manually load the dependencies:

> libra开发者_StackOverflow社区ry(zoo,  lib=libPath)
> library(fda,  lib=libPath)
Loading required package: splines

ok, that worked. Now let's try sde:

> library(sde,  lib=libPath)
To check the errata corrige of the book, type vignette("sde.errata")

WTF? it loaded fine?!?

So why can I manually load the packages but R is not picking them up automagically?

Adding to my confusion, I discovered during debugging that if I don't use the lib=libPath then everything works just fine. So it looks like the use of a custom path for packages is screwing this all up... but why?

You confirmed my suspicions in the comments. You need to do one of two things:

.libPaths(libPath)

or

library(sde,  lib=c(libPath,.libPaths()))

I prefer the first method because the second requires you do that for all calls to library.