When I try to install the hightrokghput assays workflow The following happens:
> source("https://bioconductor.org/workflows.R")
Bioconductor version 3.4 (BiocInstaller 1.24.0), ?biocLite for help
> workflowInstall("highthroughputassays")
Installing package into ‘/Users/johansenkh/Library/R/3.3/library’
(as ‘lib’ is unspecified)
Warning in install.packages :
URL 'https://bioconductor.org/packages/3.4/workflows/bin/macosx/mavericks/contrib/3.3/PACKAGES.gz': status was '404 Not Found'
Warning in install.packages :
URL 'https://bioconductor.org/packages/3.4/workflows/bin/macosx/mavericks/contrib/3.3/PACKAGES': status was '404 Not Found'
Warning in install.packages :
unable to access index for repository https://bioconductor.org/packages/3.4/workflows/bin/macosx/mavericks/contrib/3.3:
cannot download all files
installing the source package ‘highthroughputassays’
trying URL 'https://bioconductor.org/packages/3.4/workflows/src/contrib/highthroughputassays_0.99.120889.tar.gz'
Content type 'application/x-gzip' length 441585 bytes (431 KB)
==================================================
downloaded 431 KB
* installing *source* package ‘highthroughputassays’ ...
** inst
** help
No man pages found in package ‘highthroughputassays’
*** installing help indices
** building package indices
** installing vignettes
** testing if installed package can be loaded
Error : .onLoad failed in loadNamespace() for 'rgl', details:
call: dyn.load(file, DLLpath = DLLpath, ...)
error: unable to load shared object '/Users/johansenkh/Library/R/3.3/library/rgl/libs/rgl.so':
dlopen(/Users/johansenkh/Library/R/3.3/library/rgl/libs/rgl.so, 6): Library not loaded: /opt/X11/lib/libGLU.1.dylib
Referenced from: /Users/johansenkh/Library/R/3.3/library/rgl/libs/rgl.so
Reason: image not found
Error: loading failed
Execution halted
ERROR: loading failed
* removing ‘/Users/johansenkh/Library/R/3.3/library/highthroughputassays’
Warning in install.packages :
installation of package ‘highthroughputassays’ had non-zero exit status
The downloaded source packages are in
‘/private/var/folders/hb/sc3x6vtj0ys009qnyplbp2_h1g5hgm/T/RtmptgIUo5/downloaded_packages’
What should I do about it? I have tried on 3 computers (Mac).

I assume you previously had a working installation of rgl, but probably because of some system changes (?) it stopped loading. The easiest thing to try is to re-install the package.
It gives the exact same error after doing that. Further, I have tried on 2 other macs, and it wouldn't work there either.