Can't roxygenise - "could not find function "with_tz""

[datalove]

I'm trying to submit a pull request with some code and documentation, but I'm having trouble with the document part.

To check that my new local branch isn't the problem, I've just started from scratch again by using RStudio to clone the master branch of lubridate to my local machine. From there, I can build/check/test without any problems. But when I try to document, RStudio gives the following error:

==> devtools::document(roclets=c('rd', 'collate', 'namespace'))

Updating lubridate documentation
Loading lubridate
Error in eval(expr, envir, enclos) (from instants.r#82) : could not find function "with_tz"
Calls: suppressPackageStartupMessages ... in_dir -> force -> source_many -> source_one -> eval -> eval
Execution halted

Exited with status 1.

After trying and failing to document, it now gives an error when I try to build & reload (could not find function "with_tz"). Whereas prior to attempting to document, build & reload worked fine.

Any ideas what's going on?

PS: All packages are up-to-date using CRAN

==> R CMD INSTALL --no-multiarch --with-keep.source lubridate3

make: Nothing to be done for `all'.
* installing to library ‘/Library/Frameworks/R.framework/Versions/3.1/Resources/library’
* installing *source* package ‘lubridate’ ...
** libs
installing to /Library/Frameworks/R.framework/Versions/3.1/Resources/library/lubridate/libs
** R
** data
*** moving datasets to lazyload DB
** inst
** preparing package for lazy loading
Error in eval(expr, envir, enclos) : could not find function "with_tz"
Error : unable to load R code in package ‘lubridate’
ERROR: lazy loading failed for package ‘lubridate’
* removing ‘/Library/Frameworks/R.framework/Versions/3.1/Resources/library/lubridate’
* restoring previous ‘/Library/Frameworks/R.framework/Versions/3.1/Resources/library/lubridate’

Exited with status 1.

Here's my R.Version() if it matters

> R.Version()
$platform
[1] "x86_64-apple-darwin13.1.0"

$arch
[1] "x86_64"

$os
[1] "darwin13.1.0"

$system
[1] "x86_64, darwin13.1.0"

$status
[1] ""

$major
[1] "3"

$minor
[1] "1.1"

$year
[1] "2014"

$month
[1] "07"

$day
[1] "10"

$`svn rev`
[1] "66115"

$language
[1] "R"

$version.string
[1] "R version 3.1.1 (2014-07-10)"

$nickname
[1] "Sock it to Me"