Problem in downloading u-boot source code

Hi All,

I have downloaded the u-boot source from the below link,

git clone git://www.sakoman.net/git/u-boot-omap3.git u-boot_beagle

I have followed the instructions specified on elinux.org. But when
I execute the command ‘git checkout -b beagle test’, I am getting
the following error:

###error message###
fatal: git checkout: updating paths is incompatible with switching branches/forcing
Did you intend to checkout ‘test’ which can not be resolved as commit?