I was facing the exact same issue and after making a lot of searches and many different tries, this is what fixed it for me:
Download
rebase
from http://www.tishler.net/jason/software/rebase/ (download the latest *.exe version) and run it.Fire up a Prompt ("Run as administrator") and go to your
dev-kit
folder (for instance, mine wasC:\Programs\dev_kit
)While in the dev-kit folder, run
devkitvars.bat
to add devkit to the path.Now do a
cd bin
(it got me toC:\Programs\dev_kit\bin
) and from there run:rebase -b 0x30000000 msys-1.0.dll
Try to install the gems again. Instead of seeing an error message, now you should see Building native extensions. This could take a while...
and it will hang for a while there.
Your gem should be successfully installed after a couple of minutes/seconds. No more headaches :)