twitter/bootstrap — Issue #1409: [2.0-wip] Customize - Error in compilation Download
Author: Merg1255
Created: 2012-01-30 00:01:45+00:00
State: open

Go here: http://markdotto.com/bs2/docs/download.html
and click download with all options checked. The downloaded file has no css files.

Resolve issue:
uncheck "responsive layouts"

I guess this has to be fixed in the compilation script.